Abstract: In order to analyze the effects of nano SiO₂ particles on the performance of foamed concrete through addition of different quantities of nano-silica（NS）, five factors including dry density, water absorption, compressive strength, micro pore structure and thermal conductivity were tested. The results are as follows. When different proportions of NS were added（2%, 4%, 6%, 8%, 10%）, the dry density, compressive strength and thermal conductivity were all enhanced. When the mass ratio of NS was 10%, the dry density of the reference sample was increased by 7.2%, the compressive strength was 80.6% higher than that of the reference sample, and the thermal conductivity was 0.88 W/（m·K）. It shows that the performance of foamed concrete is enhanced with the increase of NS content under the condition of limited experimental design proportion. 10% content is the largest, and the corresponding improvement of foam concrete performance is also the largest. It is observed by electron microscope that with the increase of NS content, the pore size is refined and the distribution is more uniform, which can improve the thermal insulation and mechanical properties of foamed concrete.