Abstract: Application of "3414" test design scheme of the soil under different fertility levels of NPK fertilizer effect of field experiment. The results show that the high level of soil fertility, application of nitrogen, phosphorus and potassium fertilizer materials and deficiency area compared with the average increase yield was N > K > P, N the best effect, the increase rate of 21.1%; Soil fertility, low level of application of nitrogen, phosphorus and potassium fertilizer materials compared with deficiency area average yield effect of K > N > P, K application effect is best, increase rate of 25.1%, 26.0% respectively. Economic high fertility soils, this product NPK fertilizer use for for N, P₂O₅ 5.67 13.08 kg / 667 m₂ of 667 kg K₂O / 667 m₂ and 13.76 kg/m₂, best ratio of the three elements was 1:0.43:1.05, this product NPK economic fertilizer rate for N, P₂O₅ 12.76 kg / 667 m₂ of 5.87 kg K₂O / 667 m₂ and 15.49 kg / 667 m₂, the three elements of the best ratio was 1:0.46:1.21, more K fertilizer; In low fertility soils, this product NPK economic fertilizer rate for N, P₂O₅ 12.58 kg / 667 m₂ of 6.11 kg K₂O / 667 m₂ and 15.76 kg / 667 m₂, the three elements of the best ratio was 1:0.49:1.26, less amount of nitrogen and potassium application.