Coating process of organic fertilizer production for for preventing fertilizer granules caking and volatilizing. Coating agent is adhered to the surface of the granule with a powder coating machine or a liquid melting pot. Its coated granules are uniform, round, beautiful appearance and good effect. The coating machine is composed of screw conveyor, stirred tank, oil pump and main engine. Powder dusting or liquid coating process can effectively prevent the agglomeration of compound fertilizers. According to the technical requirements, the equipment has been specially designed on the internal structure. The polypropylene inner liner or acid resistant stainless steel is used in the main machine. It is an effective special compound fertilizer equipment.