According to the data of the CSS database in 2015, 2017 and 2019, the effect of the pension insurance system on adjusting the income gap between generations is analyzed through objective and subjective indicators. The conclusion shows that social transfer income is the second income source of urban workers from the perspective of objective indicators; The transfer income of pension insurance obtained by low-income group is significantly higher than that of high-income group, and some middle and high-income groups show negative income redistribution effects to varying degrees; The transfer income of old-age insurance obtained by the elderly group is significantly higher than that of the young and middle-aged group; The Gini coefficient within and between generations shows a downward trend, but the Gini coefficient between generations is still around the warning line of 0.4. From the perspective of subjective indicators, most employees have a high degree of satisfaction and fairness evaluation on pension security; The evaluation of its positive income regulation role is relatively low. Both objective and subjective indicators indicate that the endowment insurance system has played a basic security function. In terms of narrowing the gap between rich and poor and exerting positive income redistribution effect, the endowment insurance system still needs to be further improved.