||In recent years, protest activities happened frequently in Taiwan. These protests have had profound conseąuences and changed the landscape of Taiwanese politics. Therefore, it is important to know who protests and why these people protest. This paper aims to answer two questions. First, what kind of people (according to their Socio-Economic Status, SES) is more likely to participate in protest? Second, how does SES influence protest participation? Our hypotheses are drawn from grievance theories, resources model and cultural change theory. We hypothesize that in Taiwan, people with higher SES tend to join in protest. The mechanisms are material condition, civic skills, and the value of post- materialism. Empirically, taking advantage of the World Values Survey 2010-2012, we use confirmatory factor analysis to construct an indicator of SES including education, income, and class. Then, we conduct structural equation modeling to test the mechanisms through which SES exerts influences. We find that in Taiwan, people with higher SES are more likely to protest. Moreover, civic skills are the most important mechanisms. Material condition also has a positive effect. Although the value of post- materialism can influence protest participation, whether people hold this value is unrelated to their SES.