In order to realize the efficient and comprehensive utilization of coal gangue solid waste, the coal gangue leaching residue - sodium sulfate dry method was chosen to prepare sodium silicate solution with the acid leaching residue as raw materials，which was generated after valuable elements extraction from coal gangue. A high value-added silica product was prepared by a carbonization method. Determination of dibutyl phthalate oil absorption value, specific surface area test X-ray diffraction, Fourier Transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis - differential scanning calorimetry and other modern characterization methods were used to characterize the properties of silica. The concentration of sodium silicate, reaction temperature, the Na2CO3 mass concentration and CO2 ventilation rate were investigated by single factor test. Based on the single factor test, the orthogonal test design and response surface methodology were used to optimize the preparation process with specific surface area as the main index. The results indicate that the optimum process conditions are as follows: the sodium silicate mass fraction 10%, the reaction temperature 77 °C, and the CO2 ventilation rate 147 mL/min, and Na2CO3 mass concentration 3%, the verification experiment results are basically consistent with the prediction results of the response surface, under this condition, the silica product with specific surface area of 267.33 m2•g-1 and DBP oil absorption value of 2.77 mL•g-1 can be obtained. The product performance analysis shows that the product is an amorphous product composed of amorphous materials. The product has no impurities, high purity and good micro-morphology, which meets the requirements of Class A products in standard HG/T3061-2009.