Abstract: Cow dung and corncob were used as main materials for composting.The physicochemical properties and dynamic succession of microbial communities of culture materials at different composting stages were surveyed using metagenomic analysis.The experiment was divided into three stages, unfermented（C1）,first composting completed（C2）,and second composting completed（C3）,in order to explore the characteristics of tunnel fermentation of Agaricus blazei Murrill. substrates and optimize the technology.The results showed that, the moisture content, pH, total carbon and C/N ratio decreased continuously during the composting.The electrical conductivity and total nitrogen content decreased first and then increased.Firmicutes was the dominant phylum in bacterial communities during the whole period.Actinobacteriota and Deinococcota became the dominant flora in C2 phase, the relative abundance of Chloroflexi increased significantly in C3 phase.Ascomycota was the most abundant fungal phylum throughout the composting process, with a relative abundance of more than 92.5%,followed by Basidiomycota.TN,pH,C/N ratio, MC, TC and EC had significant effects on bacterial community structure, and TN had a significant effect on the bacterial community（P＜0.01）.TC,C/N ratio, MC and TN were the key factors affecting fungal communities, and the influence of TC and C/N ratio was extremely significant（P＜0.01）.