Strengthening the independent innovation ability of enterprises is the core of building an innovation-oriented country.How to effectively improve the independent innovation ability of enterprises has become a key problem to be solved in the process of building an innovation-oriented country.The formation of enterprise innovation ability is inseparable from the support of resources.However, China′s economic structure is facing transformation and upgrading, and the rules and regulations in the market economy are not perfect yet.Excessive government intervention in the financial market and unreasonable administrative control will lead to serious financial mismatch in the financial system.The existence of financial mismatch has a complex impact on all aspects of China′s economic activities, and enterprise innovation is one of the important aspects. 

Based on the financial mismatch phenomenon existing in the financial market, this paper uses the micro data of China′s private listed companies from 2003 to 2015 to calculate the financial mismatch index and external financing dependence, and adopts the systematic GMM method to verify the impact of financial mismatch enterprise innovation from the perspective of political correlation.The results show that financial mismatch significantly inhibits enterprise innovation output, especially for invention patents with high gold content, and the political association of private enterprises has a significant negative regulating effect on the relationship between them.By further exploring the regulating mechanism of political association activities, it is found that the regulating function of political association is to influence the relationship between financial mismatch and enterprise innovation output by affecting the external financing constraints of enterprises.

The findings of this study have the following two contributions.First of all, the research of this paper reveals to some extent the mechanism of financial mismatch influencing the innovation of China′s private enterprises, thus providing new evidence for the innovation and development of China′s private enterprises.That is to say, because the government′s administrative monopoly of the market, making the financial mismatch in financial markets, leads to the financing cost is generally higher than that of state-owned enterprises, private enterprises at the same time because of the private enterprise itself "limits", such as small scale, weak anti-risk ability, lack of collateral and other objective factors, makes the mismatch form the financial factors of high cost further with serious financing constraints problem of private enterprises, thereby inhibiting its innovative activities.Secondly, the conclusion of this paper finds that a good political association with the government can reduce the negative effect of financial mismatch on innovation activities of private enterprises.Political association activities can through information effect and resource effect to alleviate financial wrong matching private enterprise financing constraints problem, the conclusion is not only support the political association activities can help private enterprises to obtain scarce resources under government control "helping hand" point of view, and also provide a new angle of view for the development of the theory of enterprise innovation.

The research conclusion of this paper has positive enlightenment significance to improve the innovation activities of private enterprises in China.

First of all, is conducive to further improve the marketization of the financial system in China, get rid of the government′s administrative intervention. The freedom of the financial markets to relieve the state sector financial "crowding out" of the private sector and the private sector in the political affiliated enterprise of non-political affiliated enterprise financial "crowding out", correct financial mismatch phenomenon in financial markets.To create a relatively fair competitive financing environment for different ownership and different types of enterprises in the private sector.

Secondly, we should promote the establishment of a more perfect formal guarantee system to further improve the macro policy environment for the development of private enterprises.Private enterprises are faced with many institutional problems in the process of development. Only by establishing a complete formal guarantee system can the operational risks of private enterprises be reduced and the good expectations of market subjects and fund suppliers for the healthy growth of private enterprises be enhanced.

Finally, enterprises should strengthen their own capacity building and improve their financing capacity.Compared with other activities, enterprise innovation activities face more severe external financing constraints, which are not only related to financial mismatch at the macro level, but also related to enterprise self-construction at the micro level. In order to eliminate the information asymmetry between enterprises and financial institutions to the greatest extent.Enterprises should strengthen the construction of their own credit system and establish a sound information disclosure system, so as to ease the external financing constraints faced by enterprise innovation activities.