Studying the fertilization effect of walnut and the recommended fertilization amount for the best benefit in southern Xinjiang can provide a theoretical basis for the efficient utilization of fertilizers.This study selected Yecheng County as the specific research area，and the research on the effect of walnut fertilizer was carried out based on the “3414+2”experimental plan.The univariate quadratic and ternary quadratic fertilizer effect functions were used for fitting，and then the N，K2O and P2O5 fertilization amount of walnut in southern Xinjiang were optimized.The results showed that:(1)Different fertilization rates had a significant impact on the walnut yield，which the yield and quality of N2P2K2 treatment were significantly higher than other treatments.The correlations between different nitrogen fertilizer treatments and walnut yield were significant，while the effects of phosphorus and potassium fertilizers on quality were more significant；(2)The fitting degree of the ternary quadratic regression fertilizer efficiency equation was significantly higher than that of the univariate quadratic equation.The recommended walnut fertilization rate calculated based on the fitting results showed that the N，P2O5 and K2O reached the optimal amount of fertilizer under the scenario of walnut yield as the main target.The dosages were 0.21，0.59 and 0.58 kg/plant，respectively，the optimal fertilization ratio was 1.0∶2.8∶2.7，and the predicted optimal yield was 8.90 kg/plant.In order to pursue the quality of walnuts，the optimum application rate ranges of N，P2O5 and K2O were 0.55～0.64，1.37～1.50 and 0.56～0.62 kg/plant，respectively.Based on the“3414”fertilizer efficiency test and the regression calculation of the ternary quadratic fertilizer efficiency equation，the NPK recommended fertilization amount and its ratio can provide a scientific basis for the precise fertilization of walnuts in southern Xinjiang.