Wollastonite and hydrochloric acid react quickly when the pH value is not higher than 1.5. This paper studies the chemical conditions and distribution of such elements as Si,Ca, Fe and Mg in solid phase and liquid phase after reaction. When the pHvalue is 0.3~0.6,the ratio of silica in liquid phase (silica sol) is the highest. Ca is mainly in liquid phase, with always a little in solid phase. The specific surface area of solid phase is large in rapid reaction.If PEG is added to the system before reaction and the PH value is adjusted to 4 after reaction, porous silica with specific surface area larger than 430 m2/g and pore size of 1~2 nm can be prepared. The product can be used in the preparation of nano-composite based on silica and catalyst holder.