By means of the quadratic general rotary unitized design, the comprehensive effects of H2O, N and K2O fertilizers on pepper yield were studied, three water-fertilizer coupling regression models demonstrating the relationships between the yield and the factors were established. Results showed that: The increasing effect of three factors on pepper yield was in an order of N＞H2O＞K2O. There were interactions between the factors, positive correlations existed between H2O and N, H2O and K2O, N and K2O at the levels lower than 0.500 and 1.682, 0.501 and 0.000, 1.685 and -1.345 respectively, but negative correlestions existed when higher than the above levels. Computer simulation showed that the highest pepper yield was 52.75 t/hm2 with the corresponding amounts of water irrigation, applied nitrogen and potassium fertilizers of 2,627.2 m3/hm2, 2,156.3 kg/hm2 and 580.3 kg/hm2 respectively. The estalished models were verified to be accurate and reliable.