In the community building campaign launched at the beginning of this century in urban China, the transfer of welfare responsibility to communities and democratization at the grassroots level both have featured prominently. Participation on the part of community residents as volunteers and voters are indispensable to the success of these initiatives. Therefore, grassroots state agents are eager to solicit involvement from those susceptible to their mobilization, including Communist Party members. In this article, we intend to investigate the role of Party members in community volunteering and voting and its differentiation across various social groups and neighborhood contexts. Drawing on nationally representative data, we find that Party members indeed have a stronger propensity to participate than the non- member residents. The effect of Party membership is statistically significant on volunteering but not on voting, and more distinguishable among employed than retired residents. In danwei neighborhoods, the direction of Party membership’s influence is reversed. These findings shed some light on the targets, emphasis, channels and constraints of Party-state’s grassroots mobilization in its quest of maintaining legitimacy in a cost-effective way.