Objective To explore the influence of social activity on depression in Chinese older adults. Methods Using the data of 2018 China Health and Retirement Longitudinal Study（CHARLS）, the effect of social activity on depression in 6 328 elderly people aged 60 years and older was analyzed by running 4 logistic regression models which sequentially controlled the general information, health status, length of sleep and activity of daily living of the elderly.Then restricted cubic spline was drawn based on the mo-dels. Results Among 6 328 older adults, the rate of having depressive symptoms was 44.56%.Social activity was a protective factor for depression in elderly people （OR=0.952,95%CI： 0.926-0.978） after controlling for the confounders.The restrictive cubic spline model showed a consistently decreasing risk of depressive onset with increased social activity （P＜0.05）. Conclusion Elderly depression is affected by social activity. Improving their social activity is beneficial to prevent the occurrence of depression.