Abstract: Trinomial one time regression orthogonal design was used to fertilize the tomato sweet pepper with N, P and K according to prescription and study its effect on yield and quality. The results showed that the effect on yield was N>P>K, and they interact each other. The polynomial regression equation, obtained as follow ＝37.71＋8.14 X1＋4.61 X2＋2.06 X3＋1.6 X1X2±13.80, accords with the real values. The sugar, ascorbic acid content will increase when much N was fertilized, as well as P and K. The reducing sugar, sucrose, and Vc content of tomato sweet pepper were highest and reach 4.8%, 0.47%, and 175.39mg/100g when 20.9kg K, 5.7kg P2O5, 25.1 kg K2O (treatment 1) were fertilized in 666.7m2, respectively. The total sugar and Vc will decrease when higher P and K were fertilized at lower N. It was not obvious for the total sugar and Vc enhancement when P and K were increased at low N. The reasonable fertilizing according to prescription of N, P and K will increase the yield and quality of tomato sweet pepper.