Method for producing organic fertilizer by using municipal sewage sludge

The invention relates to a method for producing organic fertilizer by using municipal sewage sludge. In the method, the municipal sewage sludge is fermented for the second time to be prepared into agricultural organic fertilizer or is further processed to be prepared into biological organic fertilizer or organic-inorganic compound fertilizer, the municipal sewage sludge is composted to be harmless municipal sewage sludge, and then, the municipal sewage sludge is prepared into the organic fertilizer to be applied to the soil. The invention can effectively improve the soil fertility, improve the crop yield, realize the purpose of recycling resources and relieve the processing cost by using incomes, and has positive significance for treating and recycling municipal sewage sludge and promoting low carbon economy.