Abstract: Sodium fluoride and silicon dioxide were prepared by direct one-step process out of fluosilicic acid and sodium carbonate, the by-products of phosphatic fertilizer factory. The effects of reaction ratio of raw materials, reaction temperature, reaction time, pH value of the solution on the reaction products are discussed. The products obtained meet national standards. As the simple technology is energy efficient and mild reaction conditions, it is a new way for recovering and utilizing fluorosilicic acid and reducing its environmental pollution.