Methane is the second most important greenhouse gas as well as a typical renewable biomass energy. Currently, about 74% of the methane in the atmosphere originates from the microbial syntrophic mehanogenesis process. Research on microbial syntrophic methanogenesis is therefore very important for controlling global warming and developing clean energy. This paper mainly reviews the types of methanogens, the process of syntrophic methanogenesis and its electron transfer. The typical anaerobic syntrophic oxidation of organic matters consists of three steps that are mainly conducted by fermenting bacteria, syntrophic bacteria, and methanogens. The energy released during syntrophic methanogenesis is extremely low. The syntrophic methanogenesis process contains intraspecies electron transfer in syntrophic bacteria and interspecies electron transfer between syntrophic bacteria and methanogens. Reverse electron transfer exists in intraspecies electron transfer in syntrophic bacteria and displays as electron bifurcation and electron confurcation which both require energy input to drive critical redox reactions. Interspecies electron transfer includes three types: interspecies hydrogen transfer (IHT), interspecies formate transfer (IFT) and direct interspecies electron transfer (DIET). In the future, in order to apply the process of syntrophic methanogenesis into practice, methods of gene knockout,high through-put sequencing and computational biology could be utilized for the study of substrate and electr on transfer between syntrophic microbes and the response of syntrophic microbes to the environmental changes.