The invention discloses a special organic-inorganic compound fertilizer for shrimps and rice. The special organic-inorganic compound fertilizer comprises urea, mono-ammonium phosphate, potassium chloride, a calcium magnesium phosphate fertilizer, humic acid and a fermented and decomposed material. The preparation method comprises the following steps: crushing rape seed cakes, plant ash and plant straws, adding a microbial agent, uniformly mixing, and carrying out stack retting fermentation to obtain a fermented and decomposed material; and adding the fermented and decomposed material, urea, mono-ammonium phosphate, potassium chloride, a calcium magnesium phosphate fertilizer and humic acid into a stirrer, uniformly mixing and crushing, granulating, drying, screening, and packaging to obtain the special organic-inorganic compound fertilizer for shrimps and rice. According to the invention, the organic fertilizer and the inorganic fertilizer are combined, the economic benefit in a shrimp-rice co-cropping mode is effectively improved through scientific proportioning of the organic fertilizer and the inorganic fertilizer, the inorganic nutrients meet the growth requirements of plants such as rice and aquatic plants, the organic nutrients achieve the effects of improving soil and fertilizing water, CaO promotes the growth of lobsters, and SiO2 improves the quality of rice.