Studies on the SNS political participation have covered issues of SNS effect on political participation, electoral campaigns, and the public sphere. Such issues as characteristics of SNS political participation, the characteristics of SNS users, SNS effect on the political participation, active SNS political participants, and the impact on young people's political participation, etc. have been studied in the area of political participation effect. On the election issues, SNS impact on election turnout, voting behavior, and the election results were main research topics. Finally, the research on the public sphere mainly discussed topics of quality of SNS information and social fragmentation phenomenon. What is commonly observed across all the three subjects is that the conflicting claims appear to almost all the topics. These contradictory findings are likely to occur because variables of real politics are not fully taken into account and research variables are not strictly manipulated. We can get more accurate research results in the study of SNS political participation when we conduct cross-national research reflecting the context of real politics and also designing independent variables more in detail and elaborately.