Abstract: On the basis of explaining the theory that Internet development affects the regional innovation capability, this paper reconstructs the comprehensive index system of Internet development from four aspects of Internet construction, popularization, application and integration. Based on the panel data of 30 provinces in China from 2006 to 2017, it empirically examines the impact of Internet development on regional innovation capability and its regional differences from three dimensions: linear, non-linear and restraint mechanism. The results are as follows: under the conditions of controlling openness, urbanization, and financial development, Internet development can significantly enhance China's regional innovation capability, especially for the western and central regions. The impact of Internet development on regional innovation capability has significant non-linear threshold characteristics. With the improvement of the level of Internet development, its impact on regional innovation capability shows an inverted "U" trend, and these threshold characteristics have obvious regional differences. The impact of Internet development on regional innovation capability is constrained by innovative internal and external environments such as factor endowments and intellectual property protection, and there are complex regional differences. The conclusions of this paper are helpful to clarify the strategic direction and differentiated path of Internet development.