The utility model discloses a slow release fertilizer of a special cotton formulation. The utility model is characterized in that the granular fertilizer comprises an inner core, a middle layer and a surface layer, wherein the middle layer is wrapped on the surface of the inner core, and the surface layer is wrapped on the surface of the middle layer. The slow release fertilizer of a proprietary cotton formula can supply cotton with even nutrition in time, a middle sprayed slow release urea layer can adjust the proportion of nitrogen nutrition and prolongs an effective release period of product nutrition which hardly absorbs moisture. The cotton is conventionally fertilized for 3 to 4 times in the whole growth period, can be fertilized by the slow release fertilizer of a proprietary cotton formulation once as a basic fertilizer and is additionally and considerably fertilized once by a small amount of conventional quick-acting nitrogenous fertilizer in middle and later periods.