Discussion is an effective way of improving teaching quality. Face-to-face discussion and online discussion have their own advantages and disadvantages respectively, but they both face the challenge that how to enhance students’ participation. There are many related studies on factors affecting students’ participation, most of which are around external factors, while studies on internal factors are fewer. Spiral of Silence (SOS) theory can be applied for explaining the factors affecting people engage in public discussion, and this study apply extended SOS framework for analyzing psychological factors that affect students’ participation willingness and outspoken willingness in face-to-face discussion and online synchronous discussion. The result shows that communication apprehension can significantly hinder participation, and fear of isolation can significantly reduce outspokenness willingness. Online discussion will cause less communication apprehension and more participation willingness and outspoken willingness. Contemporary, Chinese university students have the courage to face the competition and are not afraid of expressing minority opinions, but they may fear the authority of the government and their teachers.