Abstract: Straw is a field by-product of agricultural products after harvest. The main chemical components are cellu-lose, hemicellulose and lignin. Straw-decomposing inoculant is a group of complex bacteria that can degrade macromolecu-lar substances in straw into simple compounds available for plants, and provide carbon, nitrogen, phosphorus and potassium for soil, so that straw can be returned to field. In this paper, the microbial species of degraded straw were summarized, and microbial mechanism , interaction of microbial flora and application effects of straw-decomposing inoculant were reviewed. The efficiency of the bacteria was not high, the flora dynamics were not clear, enzyme degradation mechanism was not sound, the use of straw decomposer was not clear and the maturity index was not specific, etc. Based on these issues, the authors put forward in situ screening bacteria, in-depth study of the interaction mechanism of combination of bacteria and enzyme degradation mechanism to carry out the specific use of decomposing agent research and to establish a complete set of specific criteria. With these efforts, reference could be provided for straw-decomposing inoculant breeding in the future.