Wide public participation is an important means for improving governance of megacities. The paper analyses the roles and significances of public participation in megacities governance，and evaluates the progress and deficiency of public participation in urban governance of China. Meanwhile，in the aspects of transforming the city-govern idea，completing the jurisprudence with public participation，broadening of the ways for public engagement and the proper use of social organizations，the paper also proposes countermeasures and proposals to deal with the main problems of public participation.