NOVELTY - The method comprises mixing high temperature fermented 20-30 wt.% of chicken manure, 20-30 wt% of piled plant ash with 35-50 wt% of fermented bean dregs and bean pulp, and 10-15 wt% of attapulgite powder, extruding in a paired roller extruder to obtain sheet, conveying a cement field and airing, adding the mixture to a feed crusher when the moisture content is not more than 8% and crushing, where the crushing fineness is not more than 0.1 mm, pelletizing the mixture in a disc pelletizer, controlling grain size at 1-4 mm, and conveying the granule to the cylindrical drier and drying.    USE - The method is useful for preparing mineral organic fertilizer for watermelon. No biological data given.    ADVANTAGE - The method is capable of preparing mineral organic fertilizer with improved growth, sugar and solid content, taste, yield and quality of the watermelon in an economical manner.    DETAILED DESCRIPTION - The method comprises mixing high temperature fermented 20-30 wt.% of chicken manure, 20-30 wt% of piled plant ash with 35-50 wt% of fermented bean dregs and bean pulp, and 10-15 wt% of attapulgite powder, extruding in a paired roller extruder to obtain sheet, conveying a cement field and airing, adding the mixture to a feed crusher when the moisture content is not more than 8% and crushing, where the crushing fineness is not more than 0.1 mm, pelletizing the mixture in a disc pelletizer, controlling the grain size at 1-4 mm, and conveying the granule to the cylindrical drier and drying, controlling temperature at 100-150 degrees C with the water content of not more than 2%, drying and packaging to obtain the finished product. The high temperature fermentation chicken manure is performed by mixing 70-80 wt% of fresh chicken manure with 20-30 wt.% of rice chaff or straw powder, adding 400 ml of effective microorganism (EM) stock solution, 400 g of brown sugar to 500 kg of mixture, adding water to the mixed EM stock solution and brown sugar and stirring the mixture and the chicken manure, controlling water content at 40-50%, and hermetically fermenting for 7-15 days. The piling of the plant ash is performed by feeding the plant ash to a cement tank, spraying clear water to the tank, controlling water content of plant ash at 5-20%, and storing for 10-40 days. The fermentation of the mixture of bean dregs and bean pulp is preformed by steaming 30-50 wt.% of bean dregs and 50-70 wt.% of bean pulp till the mixture can be kneaded into soft mud, adding the mixture to another cement tank and naturally fermenting, controlling fermentation temperature at 20-40 degrees C, controlling water content at 10-15%, and fermenting for 4-7 days.