Abstract: The study aims to establish winter wheat abundant or lack index of nitrogen, phosphorus and potassium in western Guanzhong District, and gain the optimum economic fertilizing guide to practice. 30 winter wheat“3414”fertilizer effect experiments were conducted in different soil fertility levels zone in Baoji Chencang District, which located in the west of Shaanxi Guanzhong from 2006 to 2010. The authors researched the relationship between winter wheat relative yield and soil available nutrients and determined soil nutrient abundant or lack index and the optimum economic fertilizing through relative equations. The results showed that, the soil nutrient can be divided into 5 levels, namely extremely high, high, medium, low and extremely low according to critical value standard of winter wheat relative yield 55% , 75% , 85% and 95% by statistical analysis of experimental data. The winter wheat soil abundant or lack index were as follows, the critical index of soil alkali-hydrolyzable nitrogen were＞110, 80-110, 50-80, 20-50,＜20 mg/kg. The critical index of soil available P were＞50, 35-50, 20-35, 10-20,＜10 mg/kg. The critical index of soil available K were＞190, 150- 190, 110- 150, 70- 110,＜70 mg/kg .The average optimum economic fertilizing of winter wheat in Western Guanzhong district were as follows, applied pure nitrogen 177.0 kg/hm2, phosphorus pentoxide 124.5 kg/hm2, potassium oxide76.5 kg/hm2 for winter wheat. Analysis results indicated that abundant or lack index of nitrogen, phosphorus and potassium and the optimum economic fertilizing of winter wheat had strong pertinence and effectiveness. It had theoretical and practical significance to instruct scientific fertilization of winter wheat in western Guanzhong District.