A method of preparing bio-based engineering rubber formed by emulsion polymerization of chemically crosslinked itaconate-butadiene copolymers, the method comprising: A: performing the emulsion polymerization of itaconate and butadiene by: mixing itaconate, emulsifier, electrolyte, activator and deionized water in a polymerization reactor, closing the polymerization reactor, removing air from the polymerization reactor using vacuum-pumping, filling the polymerization reactor with nitrogen, repeating mixing, closing, removing and filling operations for 1-5 times, adding butadiene, deoxidant, and initiator to the polymerization reactor and performing reaction for 5-15 hours in the polymerization reactor under 1-20°C, 0.1-5 Mpa, adding a terminator to terminate the reaction and obtaining bio-based engineering elastomer raw glue comprising the itaconate-butadiene copolymers after demulsification dry of emulsion, wherein a mass ratio of the itaconate, the butadiene, the emulsifier, the electrolyte, the activator, the deoxidant and the initiator, the terminator and the deionized water is: 100: 1-100: 1-10: 0.1-5: 0.01-5: 0.1-5: 0.01-5: 1-10: 100-1000, a number average molecular weight of the itaconate-butadiene copolymers is about 53000-1640000, a weight-average molecular weight of the itaconate-butadiene copolymers is about 110000-2892000, and a molecular formula of itaconate is: wherein R 1 and R 2 are H or C 1-10 alkyl, and R 1 R 2 are same or different; and B: performing vulcanization process based on the obtained bio-based engineering elastomer using sulfur as a cross-linking agent in a sulfur vulcanizing system under 140-160°C to prepare the bio-based engineering rubber comprising the itaconate-butadiene copolymers. A: performing the emulsion polymerization of itaconate and butadiene by: mixing itaconate, emulsifier, electrolyte, activator and deionized water in a polymerization reactor, closing the polymerization reactor, removing air from the polymerization reactor using vacuum-pumping, filling the polymerization reactor with nitrogen, repeating mixing, closing, removing and filling operations for 1-5 times, adding butadiene, deoxidant, and initiator to the polymerization reactor and performing reaction for 5-15 hours in the polymerization reactor under 1-20°C, 0.1-5 Mpa, adding a terminator to terminate the reaction and obtaining bio-based engineering elastomer raw glue comprising the itaconate-butadiene copolymers after demulsification dry of emulsion, wherein a mass ratio of the itaconate, the butadiene, the emulsifier, the electrolyte, the activator, the deoxidant and the initiator, the terminator and the deionized water is: 100: 1-100: 1-10: 0.1-5: 0.01-5: 0.1-5: 0.01-5: 1-10: 100-1000, a number average molecular weight of the itaconate-butadiene copolymers is about 53000-1640000, a weight-average molecular weight of the itaconate-butadiene copolymers is about 110000-2892000, and a molecular formula of itaconate is: wherein R 1 and R 2 are H or C 1-10 alkyl, and R 1 R 2 are same or different; and mixing itaconate, emulsifier, electrolyte, activator and deionized water in a polymerization reactor, closing the polymerization reactor, removing air from the polymerization reactor using vacuum-pumping, filling the polymerization reactor with nitrogen, repeating mixing, closing, removing and filling operations for 1-5 times, adding butadiene, deoxidant, and initiator to the polymerization reactor and performing reaction for 5-15 hours in the polymerization reactor under 1-20°C, 0.1-5 Mpa, adding a terminator to terminate the reaction and obtaining bio-based engineering elastomer raw glue comprising the itaconate-butadiene copolymers after demulsification dry of emulsion, wherein a mass ratio of the itaconate, the butadiene, the emulsifier, the electrolyte, the activator, the deoxidant and the initiator, the terminator and the deionized water is: 100: 1-100: 1-10: 0.1-5: 0.01-5: 0.1-5: 0.01-5: 1-10: 100-1000, a number average molecular weight of the itaconate-butadiene copolymers is about 53000-1640000, a weight-average molecular weight of the itaconate-butadiene copolymers is about 110000-2892000, and a molecular formula of itaconate is: wherein R 1 and R 2 are H or C 1-10 alkyl, and R 1 R 2 are same or different; and B: performing vulcanization process based on the obtained bio-based engineering elastomer using sulfur as a cross-linking agent in a sulfur vulcanizing system under 140-160°C to prepare the bio-based engineering rubber comprising the itaconate-butadiene copolymers.