While relaxing the birth policy, it is of great significance to coordinate with the policy of delayed retirement. By constructing a theoretical model of postponed retirement and birth policy adjustment, we find that, from the view of labor force increase, postponed retirement will produce an immediate effect while the new birth policy adjustment is expected to have a lagging effect, and the difference resulted from the comparison tends to expand first and then contract, the node of which will be in the year 2031. From the view of social burden, after the application of postponed retirement, the general maintenance rate will decrease to a lower level and the rate of increase will be slower; from the view of the general output, the potential loss in the economy will be the least in applying the two policies simultaneously; from the view of output increase rate, the combination of relaxing birth policy and delayed retirement will make the economic increase rate decrease the slowest; from the view of output per capita, the two policies, if applied properly, will make the income per capita increase considerably.