Abstract: This review summarized research advances in the microbial communities of biogas fermentation eco systems at home and abroad,analyzed the inadequacies of the basic ecological studies,and pointed out related scientific issues.On this basis,for the basic ecological and scientific issues,research strategies were proposed.First，our aims are to establish artificial ecosystem models in the laboratory by simulating the natural environments of biogas fermentation systems in representative(s) of the climate zones of a certain region (e.g.Yunnan),and to design the pure culture isolation and cultivation systems of simulated natural environments.Second,spatio-temporal dynamics of microbial diversity,including pure cultures,community structure and function of the simulated natural ecosystem models in different fermentation stages,are to be analyzed by applying both culture-independent approaches and newly designed isolation and cultivation systems.In the meantime,the relevant dynamics of abiotic factors are to be analyzed and recorded; furthermore,the microbial community succession laws of anaerobic digestion systems,including relationships between biotic factors,biotic and abiotic factors,and abiotic factors,are to be revealed by using comprehensive analysis of ecological factors,i.e.,to reveal the basic ecological issues of the systems.In addition,based on the research results,techniques and methods for enrichment,acclimation and cultivation of highly efficient activated sludge of anaerobic digestion are to be established,and (a) promising efficient methane fermentation system(s) is (are) to be designed,which is to lie the foundation for large-scale applications.Finally,systemic isolation and cultivation strategies for uncultured microorganisms in biogas fermentation systems are to be proposed to meet the needs of scientific research,conservation and exploitation and utilization of microbial resources in the designated region.