The invention relates to the field of ecological environmental protection, in particular to an orange peel fermented organic fertilizer. The orange peel fermented organic fertilizer comprises the following raw materials in parts by weight: 30-50 parts of sludge, 30-50 parts of orange peel, 3-5 parts of Chinese herbal dregs, 3-5 parts of shell powder, 0.5-2 parts of a microelement fertilizer, 0.5-1part of a microbial agent and 0.5-2 parts of fermenting powder. The invention further discloses a preparation method of the orange peel fermented organic fertilizer. The orange peel fermented organicfertilizer is prepared from the sludge in a sewage plant, the orange peel, the Chinese herbal dregs, the shell powder, the microelement fertilizer and the like, adopts a reasonable formula and can meet various needs for crop growth; meanwhile, the Chinese herbal dregs are fully utilized, so that the disease resistance of crops is improved while wastes are utilized.