In order to study the effects of organic fertilizer substitution of chemical fertilizer on soil fertility and corn yield，a field plot experiment was conducted in Fangshan district，Beijing.Five treatments were set up: blank control(CK)，conventional chemical N fertilization(CN)，organic N fertilization with equal N with CN(ON)，organic N fertilization with half N with ON(0.5 ON)，half of chemical fertilizer nitrogen and half of organic fertilizer nitrogen(0.5 CN).The results showed that the replacement of 100% chemical fertilizer with organic fertilizer reduced the yield of corn by 5.2%～6.7%，and there was a tendency to further decrease； the replacement of 50% chemical fertilizer by organic fertilizer increased corn yield by 11.8%.The application of organic fertilizer significantly increased soil organic matter，available nitrogen，phosphorus，potassium and microbial biomass.For organic fertilizer substitution of 50% chemical fertilizer nitrogen treatment，the soil available nitrogen and available potassium increased by 53.2% and 38%，and this treatment had a significant positive correlation with corn yield.The replacement of 50% fertilizer nitrogen by organic fertilizer can increase soil microbial biomass carbon and urease activity，improve soil properties and increase soil particle size ratio of 0.01～0.05 mm，which is worthy of popularization.