The microstructure and mechanical properties of Ta33W35Cr15V17/Al2O3 nano-multilayer films with preset defects after He+ ion irradiation were studied to understand the effects of layer interfaces and nano-defects. After irradiation, the growth of He bubbles in the alumina layer was confined to the nanovoids without aggregations. The nanochannel in the high-entropy alloy layer absorbed the deposited energy of He+ and shrank to disappear. In addition, the film was softened after irradiation due to the presence of presetting defects. Based on which a dual absorption source model of interface and pre-set defects was proposed to explain the enhancement of radiation tolerance.