In order to clarify the effect of longterm fixed application of chemical nitrogen partly replaced by different organic nitrogen on soil nutrition in winter wheat continuous cropping,a successive 11year field test with same winter wheat cultivar was conducted in loessial soil areas in eastern Gansu province of the Loess Plateau.The change of soil nutrient content was compared with no fertilizer(CK),applied equal amount of nitrogen and phosphorus nutrient with three kinds of organic material(biological organic fertilizer,straw returned and farmyard manure)or nitrogen and phosphorus fertilizer.The results showed that compared with CK,the organic fertilizer significantly increased the 0～60 cm soil NO-3N accumulation amount after winter wheat harvest in 2016.The amount of organic matter,total and available N,P,K content within 0～60 cm soil layer decreased gradually with the increase of soil depth,and 0～20 cm soil layer had the highest contents of nitrate nitrogen,organic matter,total and available nitrogen and phosphorus.Based on the average soil nutrient content in 0～20 cm soil layer,organic fertilizer significantly increased the soil organic matter,total nitrogen,total phosphorus,total potassium,available nitrogen,available phosphorus and available potassium content.Compared with CK,the soil organic matter,total nitrogen,total phosphorus,total potassium,available nitrogen,available phosph.42%，14.94%，14.06%，2.84%，10.87%，100.7%，41.58%,respectively,for the biological organic fertilizer;and increased by 7.20%，10.34%，9.38%，1.46%，9.24%，54.66%，8.82%,respectively for the straw return.Therefore,in the study area,combined application of organic fertilizer and chemical fertilizer,especially potash fertilizer can be the most reasonable fertilization option,which can maintain the soil nutrient balance and promote the soil productivity.