Based on the 2015 data from the China Health and Retirement Longitudinal Study （CHARLS）， this study determined the utilization of outpatient and inpatient services among middle?aged and elderly people in China， and investigated and compared the differences in the influencing factors between them by the chi?square test and Logistic regression analysis. The results showed that the four?week morbidity rate among middle?aged and elderly people was 29.5%， the four?week outpatient visit rate was 20.2%， and the proportion of middle?aged and elderly patients who needed outpatient care in the last four weeks but did not visit the clinic was 31.4%. Besides， the one?year hospitalization rate of middle?aged and elderly people was 14.0%， and the proportion of middle?aged and elderly patients who needed inpatient care in the last year but did not get hospitalized was 28.8%. For the influencing factors of health services utilization of outpatient and inpatient services of middle?aged and elderly people， the same factors included the condition of chronic diseases， the type of medical insurance， economic level， self?reported health， and whether having physical examination in the past two years， gender and age are different influencing factors of outpatient and inpatient service utilization. It was strongly recommended to develop a prevention and treatment system for chronic disease by the concerted efforts among government， society and individuals. First， the hierarchical medical system should be improved to enhance the accessibility of health services. Second， while improving the income of residents， the coverage of medical insurance should be expanded to reduce the financial burden of the middle?aged and elderly. Third， health education for middle?aged and elderly people should be strengthened to enhance their health awareness.