Reasonable nutrient supply is particularly important for the high-quality and high-efficiency production of substrate-cultivated vegetables. The effects of different fertilization rates and combined application ratios of nitrogen，phosphorus and potassium on the yield and quality of substrate-cultivated pepper in Gobi Desert solar greenhouse were studied to obtain the appropriate amount of nitrogen，phosphorus and potassium and nutrient ratios for substrate-cultivated high-yield and high-quality pepper. An experiment of three factors and five levels of quadratic regression orthogonal rotational combination design was carried out，and a mathematical model was constructed with the yield and quality as the objective function，and the application amounts of nitrogen(N)，phosphorus(P) and potassium(K) as three factors of dependent variables. The research results showed that N，P and K had significant effects on the yield and quality of substrate-cultivated pepper，the order of effectson on pepper yield was K>N>P and on the pepper quality was N>P>K. When the amount of N，P and K reached 376.22，164.41 and 595.31 kg/hm²，respectively，the effect value of marginal yield decreased to 0；When the amount of N，P and K reached 245.13，115.65 and 367.13 kg/hm²，respectively，the effect value of marginal quality decreased to 0. The interactions of N-P，N-K and P-K had a strong promoting effect on yield，the interaction effect of K was greater than P for N，the interaction effect of K was greater than N for P，and the interaction effect of N was greater than P for K. The model simulation result showed that，when the pepper yield exceeded 53000 kg/hm²，the optimum fertilization rate was N 233.36～307.76 kg/hm²，P 112.71～149.74 kg/hm² and K 360.01～475.88 kg/hm². When the comprehensive score of pepper quality was more than 84，the optimum fertilization rate was N 193.12～267.17 kg/hm²，P 90.74～153.19 kg/hm² and K 289.67～437.25 kg/hm². In this experiment，when the optimum fertilization rate was N 233.36～267.17 kg/hm²，P 112.71～149.74 kg/hm² and K 360.01～437.25 kg/hm²，the yield reached to 53000 kg/hm² and the quality grade was larger than 84. The most suitable ratio of N，P2O5 and K2O was 1∶0.48∶1.54.