In order to explore the mechanism of social support in the relationship between anxiety， depression，and sleep quality，the study used a multi-stage cluster random sampling method to select 950 rural older adults in County C of Anhui Province and conducted questionnaires using survey tools such as the Pittsburgh Sleep Quality Index，the Generalized Anxiety Scale -7，the Patient Health Questionaire -9，and the Social Support Rating Scale. The results showed that the anxiety score of rural older adults was 3（0，9），while the depression score was 5（0，10）. The sleep quality score among the sample was 8（4，12），and the social support score was 37（30，42）. Anxiety，depression，and sleep quality were positively correlated，and the mediation effect test showed that social support played a partial mediating role in the impact of anxiety and depression on sleep quality. The results suggest that enhancing the level of social support can help improve the sleep quality of anxious and depressed rural older adults.