TECHNOLOGY FOCUS - BIOLOGY - Preferred Components: The decomposing inoculant comprises 50-60% Bacillus psychrosaccharolyticus, 20-30% Geobacillus stearothermophilus and Bacillus thuringiensis (remaining amount) calculated according to the number of viable cells. In the step (ii), the secondary seed fermentation culture medium for Bacillus psychrosaccharolyticus comprises 0.5-5 g/l corn powder, 5-10 g/l glucose, 5-25 g/l soybean meal, 2-10 g/l peptone, 1-5 g/l calcium carbonate, 0.1-2 g/l dipotassium hydrogen phosphate, 0.2-2 g/l magnesium sulfate, and 0.01-1 g/l manganese sulfate, where pH of the medium is 6.5-8.5. In the step (ii), the secondary seed fermentation culture medium for Geobacillus stearothermophilus comprises 1-5 g/l starch, 2-10 g/l glucose, 5-30 g/l soybean meal, 1-5 g/l peptone, 1-10 g/l calcium carbonate, 0.1-2 g/l dipotassium hydrogen phosphate, 0.2-2 g/l magnesium sulfate, and 0.01-1 g/l manganese sulfate, where pH of the medium is 6-8. In the step (ii), the secondary seed fermentation culture medium for Bacillus thuringiensis comprises 2-7 g/l starch, 2-10 g/l glucose, 5-20 g/l soybean meal, 0.1-1 g/l peptone, 1-10 g/l calcium carbonate, 0.1-0.5 g/l dipotassium hydrogen phosphate, 0.1-0.5 g/l magnesium sulfate, and 0.01-1 g/l manganese sulfate, where pH of the medium is 6-7.5. The microbial decomposing inoculant has decomposition rate of 7-20 days in summer and 15-30 days in winter. Preferred Method: In the step (i), the rotating speed of the constant temperature shaker incubator is 150-220 revolutions/minute. In the step (ii), the rotating speed of the fermentation tank is 100-150 revolutions/minute. In the step (iii), the rotating speed of the production fermentation tank is 200-300 revolutions/minute. In the step (iii), initially fermentation is carried out for 10 hours at the rotating speed of 200 revolutions/minute and the aeration rate of 100 l/minute, then the fermentation is carried out for 10-16 hours at the rotating speed of 300 revolutions/minute and the aeration rate of 150 l/minute, and the fermentation is terminated after 16 hours, where the rotating speed is 200 revolutions/minute, the aeration rate is 120 l/minute, and the total fermentation time is 18-24 hours.