Abstract: In order to improve fertilizer utilization rate, effectively improve seed traits, and improve the optimal ratio of N, P and K for seed yield and quality of Larix kaempferi seed orchard. Taking the ramets of L. kaempferi grafted clones with normal flowering and fruiting for about 30 years as the research object in Shaba L. kaempferi/Picea national seed base in Gansu Province, the random experimental design was adopted, and fertilization ratio levels of N₁P₁K₁, N₁P₂K₁, N₁P₁K₂ were set up, and no fertilization was used as the control N₀P₀K₀. The effects of fertilization at different ratio levels of N, P, K on seed traits were studied, SPSS 16.0 was used for variance analysis and multiple comparisons. The results showed that there were significant differences in the effects of fertilization with different ratios of N, P and K on seed traits of L. kaempferi seed-bearing mother plants (P < 0.05). Fertilization with different ratios could promote the effective improvement of cone and seed traits. The 1000-grain weight of fertilization with different ratios of N₁P₂K₁, N₁P₁K₁ and N₁P₁K₂ increased by 38.1%, 32.1% and 30.0% respectively compared with the control. N₁P₂K₁ has the most significant effect. The fresh weight of cones and the average seed weight of single cone are 2.08 and 2.26 times of the control (N₀P₀K₀), and 1.53 times of the fertilizer ratio level of N₁P₁K₂, 9.4% and 30.0% higher than the fertilizer ratio level of N₁P₁K₁. Fertilizing in L. kaempferi seed orchard for about 30 years can effectively improve seed quality and yield, and the N, P and K fertilization ratio level is N₁P₂K₁.