Abstract: A field experiment was conducted to study the impacts of N,P,K nutrition and their combination matches on the growth of leaves,stems and roots,and the infection rate of root rots and purple root rots of Astrgalus membranaceus (Fisch) Bge. The results show that fertilizer-N is very useful for the growth of roots and leaves,fertilizer-K can promote the growth of roots and increase the root-shoot ratio. Fertilizer-P can increase the infection rate of root rot,fertilizer-N and fertilizer-P may cause an opposite effect. Fertilizer-P increases the infection rate of purple root rots.fertilizer-N's function is not obvious.Mixing fertilizers rationally improve the yield of the root of Astrgalus membranaceus(Fisch)Bge.K fertilizer can improve the disease resistance of Astrgalus membranaceus(Fisch)Bge.