Objective: To exploring the relationship between college students’ mobile phone addiction, social support and depression. Methods: During May 2019, 1 703 students from five universities in Shandong Province were selected to complete a questionnaire composed of Mobile Phone Addiction Tendency Scale(MPATS), Perceived Social Support Scale(PSSS) and Center for Epidemiological Studies Depression Scale(CES-D). Results: The scores of mobile phone addiction, social support and depression among college students were(32.84±9.30)(67.20±11.09)(11.61±8.65). The mobile phone addiction and depression score of the low social support group were significantly higher than those of the high social support group( t =10.01, 15.89, P <0.01). Regression analysis showed that mobile phone addiction in the high social support group explained the depression variation to lower than the low social support group( R 2=0.16, 0.19, P <0.01). Social support had a partial mediating effect on mobile phone addiction and depression. The median effect value was -0.10, accounting for 21.0% of the total effect. Conclusion College students’ social support has partial mediating effects on the influence of mobile phone addiction on their depression. Improving the social support level of college students is advantageous to reduce the negative impact of mobile phone addiction on their depressive symptoms.