The invention relates to a blend of PPC, PBAT, PCL and PBS and a preparation method thereof. The blend consists of PPC, PBAT, PCL, PBS, an end-capping reagent, a lubricating agent and modified precipitated calcium carbonate. The preparation method comprises the following steps of: carrying out cold mixing on the PPC, the PBAT, the PCL, the PBS, the end-capping reagent, the lubricating agent and the modified precipitated calcium carbonate in a high-speed stirrer at the temperature not above 35 DEG C; and extruding and granulating cold mixed materials by a screw extruder, wherein the temperature of extruding and granulating is not more than 200 DEG C. With simple process method and common equipment, the invention is especially suitable for industrial production; meanwhile, the used materials are simple and easily obtained and can also be purchased in the market; the temperature of pastiness caking blocks of the blend processed by the method is greatly improved in comparison with pure PPC and the mechanical property of the blend is greatly improved in comparison with the pure PPC; and the blend widens the application range of the pure PPC and can be completely biodegraded.