Analyzing the impact of environmental policies on environmental directed technical change and its mechanisms has important theoretical and practical significance for Chinese energy conservation， emission reduction and green low-carbon development. Firstly，it analyzed the effect mechanism of environmental tax and R&D subsidies on environmental directed technical change on the basis of expanding ACEMOGLU’s environmental directed technical change model； then it used standardized supply surface system method to measure environmental directed technical change index of 30 provinces in China from 1997 to 2017. Based on it， the dynamic spatial panel model was used to empirically analyze the impact and mechanism of environmental taxes and R&D subsidies， as well as their combinations on environmental directed technical change. The results show that China’s environmental technical change is generally biased towards cleaner production， but there are still many provinces in which environmental technical change is biased towards non-cleaner production. There is a significant U-shaped relationship between environmental taxes and environmental directed technical change， while environmental taxes in most regions of China are below the inflection point， that is， environmental taxes make environmental technical change biased non-cleaner production. The combination of subsidies and policies is significantly conducive to environmental technical change biased cleaner production. Environmental taxes， R&D subsidies and their policy combinations all affect the environmental directed technical change by suppressing price effects and expanding market size effects， but the price effect caused by environmental taxes is greater than the market size effect， white the market size effect caused by the combination of R&D subsidies and policies is greater than the price effect.