The horizontal production process of 　　 polyurethane rubber roller belongs to the technical field of rubber chemical industry. The technical problem to be solved is to provide a horizontal production process of a large polyurethane rubber roller to improve the overall physical properties of the rubber roller. The horizontal production process of large polyurethane rubber rollers includes melting and mixing of raw materials, synthesis of prepolymers, pretreatment of rubber roller casting molds, casting molding, vulcanization and grinding processing steps; among them, the pretreatment steps of rubber roller casting molds are The rubber roller casting mold is placed horizontally and heated to 80-85°C; the casting molding step is casting molding under the condition that the temperature is maintained at 80-85°C. This method improves the casting method, and the product has fewer defects, good appearance, and excellent overall performance.