Abstract:     Under the background of national innovation-driven strategy and Internet as the new driving force of economic development, this paper links technological innovation with Internet development, and tries to analyze the impact of rapid development of Internet technology on technological innovation through logical analysis and empirical verification. Firstly, this paper makes a theoretical analysis of the impact mechanism of Internet development on technological innovation:(1) under the Internet environment, the information flow among enterprises, consumers, other scientific research institutions and financial institutions is frequent and sufficient, which can effectively reduce the uncertainty of technological innovation.(2) the popularity of Internet technology enables consumers to obtain information advantages, and enterprises gradually lose their dominant position in transaction negotiation, forcing them to compete in product development and services, and intensifying competition among enterprises.(3) financial models represented by P2P lending platforms, crowdfunding financing platforms and big data financing emerged at the right moment, increasing financing channels for enterprises and effectively alleviating external financing constraints.(4) business model innovation transforms the traditional commodity-oriented logic into a service-oriented logic. Based on the information provided by customers, enterprises can dig deeply into customer needs, expose product defects and implement the development of new technologies. Customer needs are different and constantly changing. The high degree of interaction between enterprises and customers maintains the market perception and promotes diversified and personalized product innovation.(5) the information platform provided by the Internet facilitates innovation subjects to purchase domestic technologies or introduce technologies. Technology spillover enables enterprises to directly access to "high technology" and obtain mature innovation results, which to a large extent saves enterprises capital and human resources, effectively reduces the research and development cycle, and promotes technological innovation. Two hypotheses are proposed based on above analyzes: H1: the Internet promotes technological innovation by accelerating the depreciation of patents; H2: Internet technology promotes technological innovation by promoting domestic and foreign references of patents.
    In the empirical analysis part, based on the relevant data of Internet related employees, Internet penetration rate, number of mobile Internet users and Internet related output, this paper uses principal component analysis to construct the Internet development index, which is used as the proxy variable of Internet development, and uses the panel data of 230 prefecture level cities in China from 2007 to 2014 to conduct empirical research. Considering the causal relationship between the development of Internet and technological innovation, the development of Internet promotes technological innovation, and the continuous progress of science and technology provides technical support for the development of Internet. Therefore, the interaction between the fixed telephone number per 100 people and the telecom investment in 1984 is taken as the instrumental variable of the urban Internet development index. The patent data used in this paper mainly have four aspects. The first is the effective patent variables including effective patent increment, effective patent stock and total effective patent). The second aspect is the invention patent variables(the number of invention patent applications and annual invention authorized patents) and the city innovation index. The third is invalidation patent, which includes invalidation patent increment, invalidation patent stock and invalidation patent quantity. The fourth is patent influence, which includes three dimensions: domestic cited, foreign cited and total cited. The empirical analysis is conducted in two aspects. The first part is the overall impact of Internet development on technological innovation, including the impact of Internet development on effective patents, invention patents and urban innovation index. The second part examines the theoretical mechanism of the influence of Internet development on technological innovation, including the impact of Internet on the renewal of innovative knowledge and the spillover of technological innovation.
     The empirical results show that:(1) internet development index has a significant positive effect on the increase of effective patent increment, effective patent stock and total effective patent. The development of Internet promotes the output of patents and effectively promotes urban innovation activities;(2) the development of Internet has significantly increased the number of invalid patents, the stock of invalid patents and the total number of invalid patents, that is, the development of Internet has significantly promoted the speed of patent invalidation.(3) the development of Internet has a significant positive effect on both domestic and foreign patent citations and the total number of citations. From the domestic point of view, the Internet as a medium makes the use of foreign patent resources by innovation subjects increase, and enterprises can carry out "secondary innovation" by using "ready-made" achievements, thus reducing the R & D investment and R & D cycle of enterprises. For foreign citation, Chinese patent cited by foreign countries intensifies competition. In order to seek a larger market and profit space, domestic enterprises are forced to strengthen innovation activities.
    The conclusion of this paper not only provides reference value for the innovation-driven strategy that China is committed to implement, but also provides practical significance for the continuous promotion of "Internet +" action plan. According to the research conclusion and the actual situation, this paper puts forward three policy suggestions on how to accelerate the construction of Internet infrastructure, how to guarantee the reasonable competition of Internet platforms and how to promote the spillover of Internet to technological innovation:(1) To further promote the "broadband China" strategy and widely promote the application and popularization of 5G and a series of new information technologies, network service providers should improve network equipment, increase access rate and reduce charges, so as to reduce the cost of Internet access for enterprises and residents and improve the utilization rate of the network.(2) It is necessary to break the mechanism barriers of traditional Internet enterprises and other enterprises, build the Internet into a big platform for enterprises to use, and promote the mutual integration and mutual promotion of Internet enterprises and other industries for common development. The government, enterprises and individuals should do the necessary protection, maintain network security, in order to ensure the healthy competition between enterprises;(3) We should make good use of the characteristics and attributes of Internet Interconnection, build an all-round and multi angle innovation network, and break through innovation barriers at home and abroad to promote innovation spillover.

Key words:  internet development, technological innovation, knowledge spillover, patent renewal