Low concentration gas reciprocating internal combustion engine power generation in coal mine is one of the main ways of gas utilization. This paper aims at the technical problem of low concentration gas power generation efficiency caused by large amount of atomized liquid water carried by gas in low concentration gas pipeline. Based on the analysis of the source of low concentration gas liquid water, this paper discusses in detail research progress of dehydration technology for low concentration gas reciprocating internal combustion engine power generation, and key discusses the mechanical separation method, electric refrigeration method, electric refrigeration combined with cold air circulation method and flue gas residual heat variable temperature method for gas dehydration of low concentration gas power generation.