Abstract:  The Internet has been playing a more and more important role in the governance. Based on the data from the 2006 Chinese General Social Survey (CGSS), this study examined the relationships between Internet use and noninstitutional political participation, such as collective petitions, unauthorized protests, and unlawful assemblies . Given that the causeeffect relationships between Internet use and noninstitutional political participation may be bidirectional, this study used the individual propensity for ICT products as the Instrumental Variable (IV) to correct for the potential simultaneity problem and other sources of the endogeneity problem, in addition to controlling for a constellation of individual demographic attributes, socioeconomic and psychological characteristics, and experiences of political participation. Considering of the popularization of mobile phones in 2000 in China, this study operationalized the IV as not owning mobile phones before 2000 while controlling for the respondents’ income around 2000. The traditional Probit estimates for the effect of daily use of Internet were negative and insignificant, whereas the IVProbit estimates were positive and significant at .05 ahpla level. According to the result of Wald test and test for weak IV, the consistent estimates of IVProbit were adopted. The findings suggest that daily Internet use did encourage noninstitutional political participation. The opposite signs of the traditional Probit estimates and IVProbit estimates might as well suggest an “inhibitory mutual relationship” between the two variables. This may imply that expanding the channel for interest expression can be one of important methods to reduce social conflicts.