The invention discloses a thermoplastic animal protein/biodegradable polyhydroxybutyrate (PHB) blended material, and a preparation method thereof. According to the present invention, 1 to 99 parts by weight of thermoplastic animal protein, 1 to 99 parts by weight of PHB, 0 to 10 parts by weight of a cross-linking agent and 0 to 10 parts by weight of a plasticizer are stirred for 5 to 20 minutes in a high-speed mixer; the resulting mixture is dried for 8 to 12 hours at a temperature of 30 to 60 DEG C; the material is then blended for 5 to 10 minutes in a double-screw extruder, with the temperature controlled at 100 to 140 DEG C; the blended material is then granulized under a temperature of 110 to 150 DEG C and a pressure of 0.1 to 1Mpa, such that the finish product is obtained. The product has good processing property, and has excellent thermoplastic processing properties and mechanical properties during procedures of extruding, blow molding, injection molding and foaming. Items produced from the product can be completely degraded after being used, and is environment-friendly. The product can be widely applied in the processing fields of chemicals, mulch films, dynamo-electrics, building materials, packaging, and environmental protection.