The results of balanced fertilization experiment carried out on the black soil at Liufangzi town of Jilin Province showed that the main limited nutritional factor affecting the high yield of soybean was K,the main limited nutritional factor affecting the fat content of high quality soybean was N and the main limited nutritional factor affecting the protein content of high quality soybean was P.Balanced fertilization not only promoted growth and significantly increased yield of soybean but also increased the content of the fat and protein.The yield of soybean was decreased by 10.6% for no potassium treatment,the fat content of soybean was decreased by 5.9% for no nitrogen treatment and the protein content was decreased by 6.28% for no phosphorus treatment as compared with the treatment of the combined application of nitrogen,phosphorus and potassium respectively.So in order to obtain the high yield and good quality of soybean,we should pay more attention to the combined application of nitrogen,phosphorus and potassium