The composite of carbon fiber reinforced polyethylene resin was prepared by using a twin-screw extruder. The effect of carbon fiber oxidation treating on the mechanical properties of carbon fiber reinforced polyethylene resin composite was researched. The tensile fracture failure mechanism of composite was analyzed for both untreated and air oxidation treated specimen. The experimental results indicate that when carbon fiber content is equal, the tensile strength and the elastic modulus of air oxidation-treated carbon fiber-reinforced polyethylene composite are improved than that of the untreated. When the fraction of adding carbon fiber is 3.99%, compared with the pure polyethylene resin matrix, the tensile strength, elastic modulus is increased by 13.12% and 172.91%, respectively. Compared to the untreated carbon fiber reinforced polyethylene resin composite, the tensile strength and tensile modulus is increased by 4.71% and 13.14%, respectively.