Investigating the effect of different fertilization on the yield and quality of Codonopsis piloula(Lu Dangshen) is essential to provide scientific evidence for standardized fertilization of Codonopsis piloula(Lu Dangshen) .A field experiment was conducted with“3414” experiment design to study the yield，contents of lobetyolin and polysaccharide of Codonopsis piloula(Lu Dangshen) and determine the optimal nitrogen，phosphorus and potassium application by fitting function model of fertilizers effect on Codonopsis piloula(Lu Dangshen) .The results showed that rational cooperation fertilizing nitrogen，phosphorus，potassium enhanced the length and diameter of root and yield of Codonopsis piloula(Lu Dangshen) ，and N2P2K2 was the most optimal treatment.According to the regression analysis of the yield and contents of lobetyolin and polysaccharide of Codonopsis piloula(Lu Dangshen) ，the optimal nitrogen，phosphorus，and potassium application amount were 103.97，107.77 and 94.63 kg·hm-2 for high yield，91.87，79.37 and 58.44 kg·hm-2 for lobetyolin yield，and 69.86，51.85 and 69.04 kg·hm-2 for polysaccharide yield，respectively.Hence，in order to achieve the coordinated development of yield and quality of Codonopsis piloula(Lu Dangshen) ，the optimal fertilizer application rates are N 69.86 ～ 103.97 kg·hm-2，P2O5 51.85 ～ 107.77 kg·hm-2，K2O 58.44 ～ 94.63 kg·hm-2.