Abstract: It is of great significance for the formulation of environmental regulation and industrial green development to examine the impact of technological innovation on industrial green growth under environmental regulation constraints and determine the optimal regulation level. The paper takes the panel data of China's inter-provincial industries from 2008 to 2017 to study the impact of technological innovation on industrial green growth under the constraints of environmental regulation. Firstly, it analyzes the influence mechanism of formal and informal environmental regulations that guide technological innovation and promote green growth based on the systematic GMM model. Secondly, it builds the panel threshold model to analyze the impact of technological innovation on green growth under the change of environmental regulation intensity, and determine the optimal regulation interval. Finally, it carries out the robustness test for the empirical study. The results show that: 1) Formal environmental regulation can either directly promote green growth, or indirectly affect it by technological innovation. Based on the constraints of formal environmental regulation, the impact of technological innovation on green growth has a double threshold, and the promotion of technological innovation is the most obvious in the interval of moderate-intensity formal environmental regulation. 2) Informal environmental regulation cannot directly promote green growth, but can help green growth by influencing technological innovation. Under the constraints of informal environmental regulation, technological innovation has a single threshold for green growth. Only in the higher level of informal environmental regulation intensity range, can technological innovation play a significant positive role. 3) Very few provinces are in the optimal regulatory range from a regional perspective.