Political communication is the soul of democracy. Previous research has found that social psychological factors play an important role in political discussion and expression. Based on the theory of the spiral of silence, this research investigates the mediating role of perceived opinion congruency in the process of offline political discussion becoming online political expression using data collected in questionnaire with a sample of 1076 Chinese young adults. This research has found that of?ine political discussion has an indirect positive relationship with online political expression through its positive relationship with perceived opinion congruency. Also, the indirect relationship is stronger at higher levels of Internet political effcacy. Research also fnds that risk perception of expression of young adults is much higher than internet political effcacy but it has no signifcant in?uence in this mediating process.