Currently, the application of the Internet and new media platforms is more convenient for people’s life and environmental governance. Based on Unified Theory of Acceptance and Use of Technology and Technology Acceptance Model, this study explores the impact mechanism and effect path of public E-government adoption in China, and constructs a new theoretical framework. The empirical analysis results show that: (1) Public expectation has a significant positive impact on their E-government adoption behavior. Performance expectancy can enhance the public’s favorable impression of the E-government platform. Effort expectancy can make the public realize that the E-government platform can be flexibly used to solve the problems around us with the minimal effort. (2) The perception of use plays a partial mediating role between public expectation and adoption behavior. Perceived usefulness affects public participation in environmental governance by affecting performance expectancy, and the perceived ease of use affects adoption behavior by affecting effort expectancy, which indicates that different perception of use has different transmission paths. (3) The platform service quality and public trust has a positive moderating effect between public expectation and E-government adoption behavior. Specifically, the better service quality, the stronger the positive impact of performance expectancy on E-government adoption behavior. The stronger public trust, the stronger the positive impact of effort expectancy on E-government adoption.