How does two-way FDI affect China's green technology innovation?

As China enters a new stage of opening up, the two-way FDI will affect the efficiency of technological innovation, which is significant to alleviate the current dilemma of resource exhaustion. In this paper, we analyze the effects of two-way FDI and other variables on green technology innovation based on the Granger test, coupling coordination model and fixed effect model, and further study the nonlinear effects with the financial development level as the threshold variable. The obtained results indicated that: (1) There is an interactive relationship between IFDI and OFDI, and two-way FDI can produce a greater positive synergy effect, with regional heterogeneity. (2) Urbanization level, property protection and government support have a positive effect on the promotion of green technology innovation. (3) The advanced industrial structure plays a suppressive role. (4) The impact of two-way FDI on China's green technology innovation level has a double threshold effect.