Abstract：Objective To investigate the mediating roles of loneliness and ruminative response in the relationship between perceived discrimination and problematic smartphone use among adolescents. Methods A survey was conducted on 1 705 middle school students by using questionnaires, which included the perceived discrimination questionnaire, UCLA loneliness scale, ruminative response scale, and smartphone addiction scale-short version. Statistical analysis was performed on the relevant data. Results Problematic smartphone use was significantly positively correlated with perceived discrimination, loneliness, and ruminative response（r=0.284, 0.432, 0.391, P<0.01）. Perceived discrimination had a significant direct effect on problematic smartphone use（95 %CI: 0.016-0.207）. Loneliness played a partial mediating role between perceived discrimination and problematic smartphone use（95%CI: 0.184-0.289）; ruminative response also playeda partial mediating role（95 %CI: 0.084-0.157）; loneliness and ruminative response together had a serial mediating effect
（95 %CI: 0.040-0.081）. Conclusion Perceived discrimination can directly affect adolescents’ problematic smartphone use and also influence it through the separate mediating roles of loneliness or ruminative response, as well as the serial mediating effect of loneliness and ruminative response.
