Abstract: The problem of low temperature breaking of guanidine gum fracturing fluid is related to the effect of coal seam penetration. In order to explore the effect of methanogenson the biodegradation of guanidine gum, Inner Mongolia some coal mine lignite were collected to prepare samples of coal samples, and the enriched fresh mine water was used as the bacteria source. The biological methane metabolism experiments of guanidine gum + coal were used to characterize the biodegradability of methanogens to guanidine gum, with the total gas production, CH₄ concentration, guanidine gum molecular functional groups and C and H elements content changes. The experimental results showed that:Adding guanidine gum can increase the production of biogas from coal, and the viscosity of the system solution is obviously reduced after metabolism; After degradation, the contents of C and H in guanidin macromolecules decreased significantly, and the surface roughness of guanidine gum increased; The main characteristic peak of guanidine gum degradation was the decrease of -OH group and C-O group, the vibration absorption peak of methyl functional group disappeared, and the content of glucuronic acid in biodegradable solution increased.