A field experiment was carried out to study the influence of different late sowing dates on growth, fresh yield, nutrient accumulation and rhizosphere microorganism of Astragalus sinicus L. Three sowing dates (Oct. 30th, Nov. 10th, and Nov. 20th) were designed according to the harvest time of rice. The results showed that late sowing date significantly influenced the growth and nutrition accumulation of astragalus, as the sowing date postponed, plant height and density, number of compound leaves per plant, fresh or dry weight per plant all decreased, fresh yield decreased significantly, highest (19 006.35 kg/hm²) on the late sowing date of Oct. 30th. No difference was found among C, N, P and K contents in the above-ground parts of astragalus on different late sowing dates, but the nutrient accumulation decreased significantly as the sowing date postponed. Late sowing date also had significant effects on population of soil rhizosphere microbes, the numbers of bacteria, fugus and actinomycetes decreased as the sowing date postponed. Fresh yield and nutrient accumulation of astragalus were lower on sowing date of Nov. 11th than that of Oct. 30th. Under the conditions of this experiment, the sowing date of astragalus should be controlled before November for higher biomass and nutrient accumulation and better effect of returning to field.