Abstract: Effects of different returnning amount of maize straw on soil fertility and yield of winter wheat was studied using randomized block design. The results showed that straw returning can increase soil organic matter content and reduce soil total nitrogen loss, enhance the capacity of soil microbial fixing and supplying C and N, increase C/N, and change the distributionof soil microbial community. Higher soil microbial C/N and redistribution of original soil microbial community was propitious to the soil organic transformation and mineralize carbon decomposition, as consequence, improve the soil nutrient supply. Our results indicate that under condition of study area, applying N 138 kg/ha, combined with returnning amount of maize straw 9000 kg/ha can enhance soil fertility and increase yield by 7.47%, significantly.