Field experiments were conducted to study the effects of organic fertilizer replacing different proportions of inorganic nitrogen on soil nitrogen leaching and corn yield in sloping farmland under the same rate of nitrogen fertilization. Treatments were set up as controlled-release urea(PCU)，organic fertilizer replaced 30% controlled-release urea(OF1)，50% controlled-release urea(OF2)，and 70% controlled-release urea(OF3)，and common urea(CU)was used as control.The results showed that the total biomass of maize in organic fertilizer treatments was increased by 8.97%～15.70% compared with CU treatment，and the grain yield was increased by 2.30%～11.66%.With the increase of the proportion of organic fertilizer replacing PCU，the grain yield increased first and then decreased，and there was no significant difference among other treatments except OF2.Compared with inorganic nitrogen treatment，the nitrogen agronomic efficiency of organic fertilization treatments increased by 1.51%～7.67%，and OF1 and OF3 had no significant difference with CU and PCU.The highest partial productivity of nitrogen was exhibited in OF2 treatment，which was significantly higher than that in PCU and CU.During the whole growth period，soil nitrate nitrogen content decreased firstly and then increased，and the values in organic fertilizer treatments were higher than common urea treatment(except seedling stage).The nitrate nitrogen content of organic fertilizer treatments was mainly concentrated in 0～40 cm soil layer，the nitrate nitrogen content of the three treatments in 40～100 cm soil layer was lower than that of inorganic nitrogen fertilizer treatments(except 60～80 cm soil layer).Except for CU，soil ammonium nitrogen content increased first and then decreased from seedling stage to jointing stage.At maturity stage，except for OF2 and CU，soil ammonium nitrogen content showed a decreasing trend.Ammonium nitrogen concentration in 0～60 cm soil layer，OF1 and OF2 in 60～100 cm soil layer of organic fertilizer treatments were significantly lower than that in other fertilization treatments，but OF3 showed no significant difference with PCU.Therefore，50% organic fertilizer replacing PCU could significantly improve maize yield and nitrogen use efficiency，increase the content of nitrate nitrogen and ammonium nitrogen in topsoil，reduce nitrate leaching into deep soil，and reduce non-point source pollution in slope farmland.