Abstract: Straw returning to field is the most effective and main way of comprehensive utilization of crop straw resources,which can be divided into direct and indirect ways.Soil microorganisms are important components of soil ecosystem and engines driving the biogeochemical cycle of soil elements,which play an important role in maintaining the system stability and sustainability.Straw returning can change soil water and heat condition,adjust C/N,and affect microbial community structure and diversity.Different straw returning methods have different effects on soil physical and chemical properties,and therefore have different effects on soil microorganisms.Conversely,changes in soil microbial community have a certain impact on the decomposition process of straw.This review mainly summarizes the effects of straw mulching and returning,deep incorporation of smashed straw and biochar on soil microorganisms.The changes in soil enzyme activity,microbial amount,microbial community structure and diversity,and microbial function are discussed.The aim of this review is to provide a theoretical basis for the selection of efficient straw mulching methods and understanding the microbial mechanism in straw