The invention relates to a method that uses city sludge to make biology organic fertilizer. It includes the following steps: mixing, dissolving, fermenting, smashing, adding additive, and fining and graining. The weight proportions of the raw material is that: (9-10)% city sludge, 65-70% swine waste or hen dung, (13-17)% stalk, (2-3)% compounding corrupting bacterium agent, and the other is fly ash, adjusting the water content to 55-65%. The additive is made up from 8% urea, 5% ammiaonia sulfate, 3% rock phosphate, 5%, 0.5%, 1%, 1%, 1%, %, 1%, 2.5%, and the other is smashed material. |