This paper aims to disclose the role of mindfulness and perceived social support (PSS) in relationship between psychological distress and sleep quality of college students. For this purpose, 480 questionnaires were issued to students from two colleges in Shaanxi, China. 443 (92.29%) of the questionnaires were returned. Then, the respondents were subject to depression anxiety stress survey (DASS-21), five facet mindfulness questionnaire (FFMQ), the PSS scale (PSSS) and Pittsburgh sleep quality index (PSQI). The main conclusions are as follows: 25.5% of college students had sleep problems and the situation was worse for females; psychological distress had a significant effect on sleep quality and mindfulness, while mindfulness acted as a mediator between psychological distress and sleep quality; the PSS regulated the effect of mindfulness on the sleep quality, and mindfulness partially mediated those with low PSS; the mediation effect of mindfulness was insignificant for those with high PSS, and their sleep quality directly hinged on psychological distress. Therefore, the sleep quality among college students can be improved by promoting their mindfulness and PSS. This research provides new insights into the field of sleep quality.