Abstract:    Improving green innovation of enterprises and building a green technology innovation system are crucial to achieving high-quality economic development. This paper manually organized China′s urban government work report and listed company green patent data from 2003 to 2015, and used the staggered DID method to examine the impact of government environmental target constraints on the quantity and quality of corporate green innovation. We found that government environmental target constraints increased the quantity of corporate green innovation, but inhibited the quality of green innovation. The mechanism analysis showed that government environmental target constraints increase the intensity of environmental regulation; R&D subsidies prompt companies to increase the number of green innovations; environmental regulations prompt companies to reduce production and emissions, increase environmental investment to lower the "compliance cost" of environmental regulations, which reduces the R&D investment of in high-quality green innovation and lowers the quality of green innovation. Further analysis found that the impact of government environmental target constraints on corporate green innovation has rich heterogeneity in terms of the intensity and type of environmental target constraints, the ownership of enterprise, social attention, and whether it belongs to the polluting industry. We have put forward some policy implications for accelerating the construction of a green innovation system. Not only must we improve the assessment system for government officials and stimulate the enthusiasm of enterprises for green innovation, but the government must also focus on supporting high-quality green innovation activities of enterprises, and promote enterprises to achieve the "quantity and quality improvement" of green innovation.

Key words: environmental target constraint, enterprise green innovation, patent knowledge breadth, environmental investment, financing constraint