The implementation of environmental policies is the key to determine the performance of environmental governance. As for the environmental policy implementation gap, scholars think that institutional arrangements are the cause of the gap, but ignore the differences of local governments’ regulatory behaviors in time series and between individuals. Analyzing this question from the perspective of signaling theory will make up for the limitations of current studies. Central government’s environmental signals can affect the environmental supervision behaviors of municipal governments to a certain extent. Municipal governments’ supervision behaviors also depend on its economic ranking. Optimizing the policy signal transmission mechanism can better mobilize the regulatory enthusiasm of the municipal governments, narrow down the implementation gap and improve the performance.