Abstract: Through the experiment applying the sludge and bacterial sludge on the farmland soil．the soil’s microorganism number can be greatly increased． Applying the sludge． the microrganism number on the sandy soi1 can increase by 109％ ，and that on the alkaline soil by 25％ ；Applying the bacterial sludge， the microrganism number on the grassy marshland soil can increase by 234％ ．that on the sandy sol1 by 44％ ，and that on the alkaline soil 56％ ．So using sludge and bacterial sludge can increase the microorganism number，raise microrganism activity and accelerate changeover of organic matter in the soil．thus increasing the fertility of soi1．