Based on statement on that internet, as a rising public sphere, provides a new platform for political participation; this paper presents the great significance of internet-mediated political participation to the democratization in public policy setting in China. Due to such existing defects as irrational, non-normative participation and all public wills represented by public opinions in the internet in internet-mediated political participation, in order to guarantee the effective development of internet-mediated political participation and its healthy and orderly promotion, Government needs to guide the public opinion in internet-mediated political participation, perfect the channels where internet-mediated political participation influences policy setting, and assure the authenticity and reasonability of internet-mediated opinions to make rational decisions.