Taking‘Tai Shan 5’potato as the object, using‘3414’fertilizer experiment design, the optimal fertilizer application under the highest yield and net income was studied by establishing a regression mathematical model of N, P, K and potato yield regression mathematical model. The results showed that the effect order of N, P and K fertilizer was K＞N＞P. While the mathematical model of a quadratic fertilizer was better than the ternary and binary quadratic fertilizer mathematical model.The yield and net income reached the highest under N₂P₂K₂ treatment for 2 685.57 kg/667 m², 6 485.22 Yuan/667 m², respectively. Compared the yield and net income, the optimum fertilizer rate of potato identified as N 24.00-25.97 kg/667 m², P 4.00 kg/667 m², K 34.00-45.16 kg/667 m², the most suitable ratio of N: P:K was 2.50:0.40:3.96.