Abstract: Based on a long-term experiment during 1979-2017 in black soil of northeast China, the objective of this study is to explore variation characteristics of soybean yield and soil physicochemical properties under long-term fertilization, and evaluate the feasibility of organic fertilizer substitution to chemical fertilizer in soybean cultivation.The experiment consisted of three treatments:chemical fertilizer(NPK, conventional application rates), horse manure(M), and 200% of the M(M₂).The results showed that:(1) long-term application of organic fertilizer did not reduce soybean yield.(2) Compared with NPK treatment, long-term organic fertilizer application(M and M₂) increased the average content of soil organic matter by 5.7% and 4.5%, respectively.There was no significant decrease in the content of alkali-hydrolyzale nitrogen and available potassium with organic fertilizer application.The content of soil available phosphorus in treatments M and M₂was significantly lower than NPK treatment, which reduced the environmental risk of soil phosphorus.The soil pH change in treatments M and M₂ was stable, thus the soil acidification could be prevented.(3) In the treatment of manure application alone, the soil bulk density and the total soil porosity in 0-20 cm soil layers decreased by 5.9%-7.5% and 7.0%-8.9%, respectively.(4) Under long-term application of organic fertilizer in black soil, the nutrient supply capacity of organic manure was strong.Application of organic fertilizer could maintain soil acid-base balance and improve soil structure.In summation, it was feasible to replace chemical fertilizer with organic fertilizer in soybean cultivation, but the organic fertilizer resources and rates should be considered in different ecological areas of black soil.