Abstract: This study focuses on the flammability of different forest litters, exploring the degradation effects of microbial agents on the combustion properties of forest litters, so as to provide new methods for forest fire prevention and control. 3m×3m sample plots were set up under populus cathayana forest, picea asperata forest, pinus tabuliformis forest and shrub forest respectively. In each sample plot, 3 1m×1m litter samples were randomly collected by diagonal method and brought back to the laboratory. Cellulose-efficient degrading bacteria and composite trichoderma agent were used for degradation treatment of the samples, and relevant indicators were measured weekly. The results showed that both agents had different degrees of degradation effects on litters of four different forest types. Among them, the composite trichoderma agent had the most significant degradation effect on pinus tabuliformis forest litters, with the highest decrease rate of crude fat content, increase rate of ash content and decrease amount of comprehensive combustion performance; the cellulose-efficient degrading bacteria had the best comprehensive cellulose degradation effect on populus cathayana forest litters (the degradation rate reached 16.37% in the 8th week); among the four forest litters, picea asperata forest had the highest comprehensive combustion performance, reaching (30.34±1.57) ng²/min²℃³. After treatment with the two agents, the largest decrease in comprehensive combustion performance was observed in picea asperata forest and populus cathayana forest litters. Combined with the macro trend of forest fire prevention, targeted application suggestions are put forward. The research results can provide a reference for the large-scale application of forest microbial agents in forest fire prevention and control.