The invention relates to the field of petrochemical industry, in particular to a hydrogenated petroleum resin granulator and a granulation method of the granulator. The granulator comprises a distributor, a conveying device, a cooling device and a discharge bin, wherein the cooling device comprises a water spray pipeline; a water spray nozzle is formed in the water spray pipeline; the water spray pipeline is arranged at the lower part of the conveying device; the water spray pipeline comprises a precooling section and a staged cooling section that are arranged in sequence; the precooling section is close to a feed end of the conveying device; the staged cooling section comprises a primary cooling section or multiple stages of cooling sections that are arranged in sequence; the precooling section and all the stages of the cooling sections of the staged cooling section are connected with water inlet pipes; the water inlet pipes are connected with cooling water; and water temperatures of the cooling water in the water inlet pipes of the precooling section and all the stages of the cooling sections of the staged cooling section are reduced in sequence. According to the granulator and the method, a temperature difference of a material and a cooling medium is kept stable; and material embrittlement and material bonding on a steel belt to result in difficult separation during rapid cooling are avoided.