Abstract: High-density polyethylene (PE-HD) film was prepared on a casting machine, and was treated by irradiation. The effect of irradiation on the structure and performance of the PE-日D film was invcsti-gated. It indicated that the toughness decreased slightly with increasing irradiation dose while the tensile and tear strengths increased. When the dose of irradiation increased from 1 Mrad to 6 Mrad，the tensile strength of MD increased from 20.5 MPa to 23.2 MPa, which of TD increased from 18.1 MPa to 19.5 MPa; the tear strength of MD increased from 11.8 mN to 17.2 mN，which of TD increased from 8 .3 mN to J.3 mN;the elongation at break changed slightly. When the dose of irradiation reached 8 Mrad，the mechanical properties were further improved.However, at higher doses, the mechanical properties decreased obviously. The content of the gel increased，which decreased the melt flow rate.

Key words: high-density polyethylene, film, irradiation, crosslinking