To investigate the optimization incorporation period of Chinese milk vetch（Astragalus sinicus)，a field experiment was conducted to study the effects of different incorporation time of Chinese milk vetch on soil nutrients，main agronomic traits in rice and rice yields.The results showed that soil available N content with Chinese milk vetch incorporated during the flowering period was 228%,110%，21%respectively higher than those in the treatments without the incorporation of Chinese milk vetch,with the incorporation of Chinese milk vetch during the beginning flowering period and after the flowering period，and 232%，115%，44%for soil available K，which indicated more nutrients was supplied by Chinese milk vetch incorporated during the flowering period.Rice yield（9 2880 kg/hm2) in the treatment incorporated Chinese milk vetch during the flowering period was 163%，49%，31%respectively higher than those in the treatments without the incorporation of Chinese milk vetch,with the incorporation of Chinese milk vetch during the beginning flowering period and after the flowering period.In conclusion，the flowering period of Chinese milk vetch was asserted as optimization incorporation period.