The resources of Cervicidae are abundant,and their feeding and digestion characteristics are different among species.As ruminants,the growth,development,physiological process and production performance of deer are closely related to rumen microorganisms.Studies have shown that genetic factors and environmental conditions affect the composition of rumen microorganisms in deer,and rumen microorganisms are related to substance utilization and methane emission in deer.In this paper,the classification,distribution,feeding habits,factors affecting rumen microorganisms and their biological functions were reviewed,in order to provide reference for rumen microecology research of deer.