In order to explore the effects of increasing organic fertilizer on the yield composition，quality and root rot of Astragalus membranaceus，the study designed different application amounts of reduced chemical fertilizer and increasing organic fertilizer in a field experiment，and measured the growth index，yield，incidence and key quality indexes of Astragalus membranaceus.The results showed that the number of root branches and lateral root diameter of pure organic fertilizer treatment(O)increased by 0.5 and 0.1 mm，respectively，compared with pure formula chemical fertilizer treatment(C)，and the root branch was significantly different between two treatment.The maximum value of fresh yield of Astragalus membranaceus was 7557.3 kg/hm² under C treatment，which increased by 45.4%，24.7% and 13.9% compared with control check(CK)，1/2C+2O and O，respectively.The yields among the three treatments showed significantly different，but did not reach significant difference with 3/4C and 3/2 O treatment.The incidence and disease index of treatment O were the lowest，and showed significant different with treatment C，which were 34.1% and 15.0%，respectively.The content of astragaloside IV in CK and treatment O was the highest，which was increased by 27.9% and 18.5% compared with the lowest treatment C(0.075%).In summary，reducing the amount of chemical fertilizer reasonably and increasing the amount of organic fertilizer appropriately will contribute to the production of high-quality Astragalus membranaceus.