This paper aims to explore the shielding potential of light-weight carbon nanotube (CNT) film materials against gamma-ray generated from americium-241 (241Am) and caesium-137 (137Cs). The influence factors of gamma mass attenuation coefficient of CNT film laminates were investigated to reveal structure-property relationship. The results showed that CNT film materials had bigger mass attenuation coefficients than carbon fiber reinforced composites, suggesting stronger radiation interaction induced by CNT’s cylindrical nanostructure. CNT alignment was proved to be conducive to the improvement of mass attenuation coefficient and gamma attenuation ratio. Aligned CNT film laminate with the thickness of 10 mm had a mass attenuation coefficient of 0.086 cm2 /g and attenuation ratio of 4.9% against gamma-ray exposed to 137Cs, which were higher than those of aluminum, iron or copper sheets. CNT film material demonstrated its potential for the application of light-weight gamma-ray safety equipment and devices.