The invention discloses a decomposing agent required for processing and recycling straw, and the decomposing agent comprises the following raw materials by weight: 0.8-1.4 parts of acrylic emulsion, 0.4-0.8 part of monoammonium phosphate, 0.3-0.6 part of Trichosporon mucoides, 6-11 parts of calcined calamine powder, 0.6-0.9 part of spore suspension, 0.6-1.2 parts of brassinolide, 0.4 to 0.7 part of Saccharomyces rubrum, 0.9 to 1.4 parts of acetic acid, 4 to 8 parts of honeysuckle extract, and 1 to 5 parts of a plant source fresh material. The decomposing agent and a fermentation process thereof have less nitrogen loss, a fermentation workshop has no pungent ammonia smell; the pH at the end of the fermentation does not exceed 8.5; the fermentation temperature of the bottom layer of compostis high, up to 45 DEG C or above, the highest temperature of the composting is up to 80 DEG C, is conducive to evaporation of water, and speeds up the drying speed of a fertilizer, the degree of accumulation of humus in the fermentation process is high; an organic fertilizer produced by the organic material decomposing agent has the advantages such as high germination rate.