To investigate the effects of different ratiosof nitrogen(N)，phosphorus(P)，and potassium(K)fertilization on the growth and leaf nutrient content of Cypomandra betaceaseedlings，taking 1 -year-old Cypomandra betacea seedlings as theobject，an orthogonal experimental design L 9(34)of three factors and three levels of nitrogen wasadopted，and no fertilization was used as thecontrol group(CK). The effects of different ratiosofN，P and K fertilization on the growth and leaf nutrient content of Cypomandra betacea seedlings were determined and analyzed. The results showed that under different fertilization ratiosofN，P andK，the accumulation of biomass in theroots，stems and leaves of Cypomandra betacea seedlings was significantlyincreased，and the distribution of biomass in each organ showed as root>leaf>stem. The nutrient accumulation in the leaves of Cypomandra betacea seedlings wasN>K>P，and the optimal treatments for leaf N and K were A3B2C1 and A2B2C3treatments，in which 6 g/plant nitrogen and 6 g/plant potassium wereadded，respectively. The plants of CK group were limited by N because ofnitrogen phosphorus ratio<14. The content of photosyntheticpigments，soluble sugars and starch were the best in A 1B3C3treatment， the activity of soluble proteins and SOD was the best in A2B2C3treatment，the activity of POD was the best in A2B3C1treatment， and the MDA content was the lowest in A2B1C2treatment，which had the best protective effect on Cypomandra betacea seedlings from damage. Correlation analysis showed that there was asignificant positivecorrelation( P<0.01)between the biomass，leaftraits，photosyntheticpigments，nitrogen，phosphorus，potassium，NSC，protective enzymes and MDA of tomato seedlingsunder different fertilization treatments. According to principal componentanalysis，the cumulative contribution rate of each indicatorreached79.69%，and the comprehensive evaluation of fuzzy membership function showed that A 1B3C3 treatment had the best effect on the growth of tree tomato seedlings. According to the comprehensive experimentalresults，the growth indicators，leaf nutrientcontent，photosyntheticpigments，protective enzymes and MDA content of Cypomandra betacea seedlings were determined. The optimal fertilization ratio was A1B3C3treatment，which applied 2.0 g/planturea，6.0 g/plantsuperphosphate，and 6.0 g/plant potassium sulfate.