The purpose of this study is to scrutinize relationships between political interests, online political participation, and conventional political participation. The research method used in this study is secondary analysis and the data are adopted from the Taiwan Communication Survey (TCS). According to the definition of political participation and due to the constraint s on the questionnaire from the TCS dataset, online political participation is respectively defined as accessibility to online political information as well as the expression and discussion of political ideas on the internet. Moreover, conventional political participation is categorized into two parts: civic movement participation and voting participation. Using stepwise regression and mediation analysis techniques, we have obtained a couple of empirical results. First of all, the effect of accessibility to online political information on participation of civic movements is indirect, which is mediated by expression and discussion of political ideas. Secondly, political interest as well as expression and discussion of political ideas have no statistically significant relationship with voting participation. Finally, although the effect of accessibility to online political information on voter turnout is statistically significant, its effect is negative which is not what we expected.