A pot experiment was conducted to study the effects of enhanced ammonium nutrition on the yield,quality and N,P uptake of summer squash in substrate culture,and to provide a theoretical basis for high quality and safety production of summer squash.Five proportions(0,10%,20%,30%,40%)of NH+4-N ratios were designed with equivalent N supply.The results showed that the growth of summer squash plants were promoted by 20% of NH+4-N,with the equivalent N supply(12.6 mmol/L).The accumulation of N in fruit was increased by 10%~20% of NH+4-N supply,and the absorption of K by the aboveground in summer squash plant was resisted by excessive NH+4-N supply.With the increase of NH+4-N ratios,the soluble sugar content in the summer squash increased but the NO-3-N content and soluble solid content decreased.The highest yield per plant was obtained at 30% of NH+4-N,which was increased by 29.6%,compared with total NO-3-N supply treatment.There were peak values of the N partial factor productivity and N harvest index at 30% NH+4-N supply.When NH+4-N supply ratio exceeded 30%,the fruit fertility rates of summer squash were below 60%,and the aboveground biomass in summer squash plant decreased significantly.To sum up,the optimum benefit of summer squash yield,quality and N utilization efficiency was achieved for the plants grown at 30% of NH+4-N supply.