NOVELTY - Plant organic matter-Bacillus subtilis HN09 mixed inoculant (plant organic matter inoculant) comprises an agricultural plant organic matter and B. subtilis HN09 strain as main component.    USE - The mixed inoculant (plant organic matter inoculant) is useful for: preventing and treating plant diseases including banana wilt and tomato blight; controlling soil pests including flea beetle and chafers; and promoting plant growth and nitrogen absorption (all claimed).    ADVANTAGE - The mixed inoculant: has synergistic effect for controlling plant pest and disease; enlarges pest control range; can completely decompose plant organic matter; and avoids harm to plants by directly using the plant organic matter (all claimed); and promotes quick composting of agricultural waste and recycling process.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing plant organic matter-Bacillus subtilis HN09 mixed inoculant, comprising (i) inoculating 5-15% B. subtilis HN09 to a nutrition broth liquid culture medium, transferring to a shaking flask, and under speed of 180 rotations/minute (rpm), culturing at 30 degrees C for 24 hours to obtain a first-stage seed liquid; (ii) adding 5-15% first-stage seed liquid to a seed tank, culturing at 28-32 degrees C under ventilation volume of 1:1 and stirring speed of 100-250 rpm to bacterial logarithmic phase, and obtaining a second-level seed liquid; (iii) adding 5-15% second-level seed liquid to a fermentation tank for culturing, where culture medium in the fermentation tank comprises 1-3% corn powder, 0.5-2% soybean powder, 0.1-0.3% yeast powder, 0.05-0.15% dipotassium phosphate, 0.01-0.03% magnesium sulfate, 0.1-0.2% calcium carbonate, and water (remaining amount), pH is 6.5-7.3, where adding 0.005-0.015 g/l manganese(ii) sulfate in the culture medium for inducing sporulation during culture condition in step (ii); and (iv) adding the resulting fermentation liquid with the plant organic substance, carrying out secondary fermentation to decompose at temperature of 20-37 degrees C for 1-60 days.