Abstract: In order to effectively improve Larix kaempferi seed traits, improve seed yield and quality, determine the reasonable fertilization level of phosphate fertilizer in seed orchard. Taking the seed-bearing mother plants of L. kaempferi clone primary seed orchard for about 30 years as the research object, the effects of phosphorus (P₂O₅) 4 levels (0, 0.18, 0.30, 0.60 kg/plant) fertilization on seed traits and cone yield per plant were studied by random experimental design. Variance analysis and multiple comparison results showed that the effects of different levels of phosphorus fertilization on seed width were significantly different (P<0.05), and there was no significant difference in seed width among fertilization levels of 0.18, 0.30, 0.60 kg/plant, but there was significant difference with the control. The effect of the 3 fertilization levels on seed width was consistent, all significantly higher than the control by 9.03%, and there was no significant difference in other seed traits and cone yield per plant (P>0.05). Although there is no significant difference in the effect on other seed traits, the average fresh weight of cones and the yield of cones per plant with phosphorus fertilization at 0.18 kg/plant are the highest, which are 5.54% and 5.36% higher than that of the control. Seed traits and yield of cones per plant do not increase with the increase of fertilization amount. Therefore, it is not recommended to apply phosphorus fertilizer alone in L. kaempferi seed orchard, and the appropriate application amount is not more than 0.18 kg/plant. Excessive fertilization not only increases costs but also causes waste.