In the group of Chinese undergraduate students, the problem of sleep quality was severe. Based on the previous research, social support had protective effect on sleep quality. The more social support individual perceived, the less sleep quality problem occurred. However, the mechanism of social support's effect on sleep quality was limited, that few researches explored the mediators between social support and sleep quality. According to Thomsen, Mehlsen, Christensen and Zachariae(2003), pre-sleep negative emotion and cognitive arousal may in...