Abstract: In order to study different fertilization amount for the effect of astragalus root growth and development, medicinal material Output and seed yield and quality, Medicinal plant Astragalus of planting in gansu province Zhangxian regard as materials. Six different fertilization treatments(A1、A2、A3、B1、B2、B3) for the effect of growth status of astragalus(plant height, branch number, root length, root diameter, fresh weight on the ground, dry weight on the ground, root fresh weight and root dry weight), medicinal material Output and seed yield and quality are compared in 2 different proportions(N:P:K=1.25:3:1、N:P:K=2:3:1). Research results show that: the effect of different fertilization treatments on Astragalus root is different, which the greatest impact is the mid growth; under different fertilization treatments, A2 treatment is advantaged to improve the yield of Astragalus root, at the same time, root fresh weight and root dry weight yield are the highest; A3 treatment have the highest seed yield; Treatment of N:P:K=1.25:3:1 of Astragalus seed production is higher than treatment of N:P:K=2:3:1, and the relative quality of the seed is also improved. A2 treatment is beneficial to improve the yield of Astragalus; while A3 treatment is beneficial to improve the yield of Astragalus seed.