Abstract: Ternary polymer was prepared using ethylene, vinyl acetate and α-olefin as the raw material, azo-bis-isobutyronitrile as initiator, through highpressure bulk polymerization. Effects of polymerization conditions on the copolymer molecular weight and VA weight content were studied. Results show that the number-average molar mass and the VA mass fraction of the ternary polymer are 8 600 and 0.35 respectively under the conditions of the dosage of initiator 1.1 g, reaction pressure 6 MPa, reaction temperature 95 ℃ and vinyl acetate and αolefin mass ratio 2∶1. The product has an excellent performance and it is suitable to be used as wax additives.