Abstract: In order to solve the purification problem of microsilica powder and improve the flotation recovery, this study introduced nano-bubbles into the flotation of micro-silicon powder, and analyzed the effect of nano-bubbles on flotation purification of microsilica powder.Nanoparticle Tracking Analysis (NTA) was used to determine the stability of nano-bubbles and the effect of sodium oleate on their stability.Results show that with the same amount of collector, the recovery of SiO₂ can be improved by introducing nano-bubbles into the flotation of micro-silica powder; When the amount of collector was 1.5 g/L, the recovery of SiO₂ reached the maximum of 70.2 %; Sodium oleate can improve the stability and dispersion of nano-bubbles in water; Nanobubbles can improve flotation recovery since there is a synergistic effect between nano bubbles and ordinary flotation bubbles produced in flotation.