Abstract:    China′s economy is in a critical period of high-quality economic development, and the new model of digital technology represented by big data economy has gradually become the driving engine of high-quality economic development. Under the tide of global digital economy, the Chinese government attaches importance to and encourages the development of the new generation of information technology and digital economy, and has carried out a series of measures for the development of digital economy, one of which is the establishment of a national big data pilot zone. Therefore, whether the digital economy focusing on the big data pilot zone can drive the high-quality economic development has become the focus of attention from all walks of life. However, the academic literature provides limited understanding of the impact of digital economy on high-quality economic development. Therefore, it is imperative for us to examine this issue in the context of a new round of scientific and technological revolution.This paper used the panel data of 286 cities from 2012 to 2018 to construct an economic quality index based on global Malmquist-Luenberger productivity. Taking the digital economy policy of "national big data pilot area" as a quasi-natural experiment, this paper used the progressive double difference model to investigate the impact of digital economy on the high-quality development of economy. It was found that the digital economy has a significant driving effect on the high-quality development of economy, mainly through the channels of improving the level of government governance, promoting intelligent development, promoting regional innovation, and optimizing industrial structure. The promotion effect of digital economy is mainly driven by technological progress, and the economic promotion effect of the central and western cities, third, fourth and fifth tier cities is stronger than that of the eastern and northeastern cities, as well as the first-tier and new first-tier and second-tier cities, and the economic promotion effect of non-resource cities is stronger than that of resource cities. With the improvement of high-quality economic development level, the economic promotion effect of digital economy is stronger than that of resource cities. The promotion effect of digital economy shows the characteristics of "fluctuation upward" change with increasing margin.The innovations of this paper are as follows. First, previous literatures mainly focused on the economic growth effect of digital economy, while few of them examined the high-quality development effect of digital economy. In fact, under the background of a new round of scientific and technological innovation, the digital economy has stimulated the transformation of economic structure and efficiency conversion, which plays an important role in promoting high-quality economic development and building a modern industrial system. This paper analyzed the internal mechanism and influence effect of digital economy on the high-quality development of economy, which will enrich the role and effect research of digital economy to a certain extent. Secondly, this paper took the policy of "national big data pilot zone" as a quasi-natural experiment to investigate the causal effect of digital economy on high-quality economic development, alleviate the possible endogeneity problems, and then obtain rigorous research conclusions. Thirdly, this paper has also contributed to the accurate understanding of the driving factors of high-quality economic development. From the perspective of digital economy development, this paper has deeply investigated the important influencing factors of high-quality economic development, and will provide theoretical and empirical explanations for China′s high-quality economic development, and help to deepen the understanding of the internal relationship between digital economy and high-quality economic development.Based on the above conclusions, this paper revealed the following policy implications. First, we should expand the coverage of the pilot zone and include other cities in the digital economy policy system, especially cities in the central and western regions and small- and medium-sized cities. Second, we should integrate regional data resources and government information integration, strengthen the development of digital, intelligent, and automated infrastructure, and continue to carry out information industry innovation. Third, we should improve the technological innovation ability and technical efficiency of the digital economy.

Key words: digital economy, high-quality economic development, national big data pilot zone, difference-in-difference method