Based on CHARLS2015, using logit regression, we explore the influence of depression on the utilization of medical services for chronically ill people from two dimensions of outpatient and inpatient, and tries to explain its influence mechanism by taking self-reported health as the intermediary. The conclusions include:(1) Depression significantly increases the utilization probability of medical services in middle-aged and elderly people with chronic diseases. The utilization probability of outpatient services and inpatient services increased by 8.4 percentage points and 4.8 percentage points respectively. (2) Self-rated health played a partial mediating role, and the mediating effect affecting outpatient service utilization and inpatient service utilization accounted for 46.02% and 63.92% of the total effect, respectively. Depression can directly and indirectly via self-rated health as the intermediary predict medical service utilization in middle-aged and elderly people.