Long-term fertilization experiment on indigenous soil of Hexi Oasis,Gansu Province indicated that 27 years.mixed use of organic manure and chemical fertilizersincr eased crop yield and its stability,especially for organic manure and NP or NPK fertilizers.Long-term use of organicmanure and chemical fertilizers in-creased N,P and K investment to soil and nutrient out put from soil as well as nutrient surplus.Soil organic matter,total N,total P,available N,available P and available K content increased by 10.0%~16.0%,58.1%~69.0%,13.4%~31.1%,45.7%~79.0%,172.2%~ 287.8%,21.4%~38.8%,respectively after 21~25 years.use of organicmanure and chemical fertilizers,and were significantly higher than those of single use of chemical fert ilizer s and the contrast.The treatment of organic manure and NPK fertilizers was the best one in improving soil fertility.