Abstract: Tailings can be used to make foamed cement insulation materials, which is an efficient means of utilizing tailings in bulk. However, the addition of tailings may have an impact on the overall performance of foamed cement insulation materials. To resolve this problem, mechanical activation of molybdenum tailings improved their volcanic ash activity, and the activated tailings were then used to make foamed cement insulating materials. The compressive strength, flexural strength, thermal conductivity and bubble pore structure of the samples were characterized to investigate the intrinsic relationship between the tailings activity and the thermal and mechanical properties of the material. The results showed that the thermal insulation properties and mechanical properties of foamed cement were enhanced with the increase of tailings activation index. The tailings were ball milled at 220 r/min for 240 min, and the molybdenum tailings activation effect was better, with the best comprehensive performance of the made foamed cement thermal insulation material.