This paper aims to study the influence of diatomite addition and amount on the release property of antioxidant and the physical properties such as tensile strength, oxygen and moisture barrier properties, heat sealing properties of HDPE/LDPE antioxidant active film. HDPE/LDPE antioxidant active film was prepared by co-extrusion casting method. The outer layer was HDPE, and the inner layer was LDPE with the diatomite as inorganic filler and ethylene-vinyl acetate copolymer (EVA) as the compatibilizer for the inorganic filler, and quercetin as the antioxidant. The release rate of quercetin was adjusted through changing the diatomite amount in the inner layer. As a result, when the diatomite amount was 0, 1%, 2%, 3%, 4%, the diffusion coefficient D (cm2/s) of quercetin were 5.91×10-13, 2.30×10-11, 1.59×10-11, 2.44×10-11 and 3.22×10-11 accordingly. With the increase of diatomite amount, the heat seal strength gradually decreased, tensile strength firstly increased and then decreased, and oxygen and moisture permeability coefficient were first decreased and then increased. In conclusion, the addition and amount of diatomite have few effects on the tensile properties, oxygen and moisture barrier properties of the film, but significantly weaken the sealing performance of the active film. Besides, the addition of diatomite made the final release amount of quercetin increased, and changing the amount of diatomite can effectively adjust the release rate of quercetin.