Sludge is performed by pretreatment, aerobic fermentation, anaerobic fermentation, drying, and addition of oxygen fermentation, dry, and add material in a certain heavy metal content. Different regions, different cities can make different organic composite fertilizers according to local sludge ingredients, and choose economic effective methods for pendant utilization of sludge. This can reduce the burden of urban pollution, sludge treatment, and promote the development of agriculture.