Abstract:Shale gas is the natural gas locked within the shale formation. It is estimated that 1/3 of natural gas is shale gas. Shale gas is found mainly in China, North America, and Russia. Hydraulic fracturing is a commonly used method to recover shale gas, which affects greatly on deep subsurface microorganisms. The microbial communities vary at different stages of hydraulic fracturing. Among them, methanogen may improve shale gas production, while the acid-producing bacteria that could corrode the equipment, may lower the gas production. With the aim of studying shale gas extraction and deep subsurface microbial interactions as well as improving extracting shale gas, this review focuses on current understandings of shale gas extraction and its impacts on deep subsurface microorganisms.