The invention discloses a preparation method of silica gel and the silica gel obtained therefrom, and relates to the technical field of inorganic silica gel. The present invention includes the following processes in sequence: rubber making, aging, tapping, washing and drying; the washing process uses magnetized water for washing, the washing temperature is 20-80°C, and the end point of washing is that the conductivity of the rubber particles is below 0.5mS / cm. The invention adopts magnetized water washing in the preparation process of silica gel, and the washing time is shortened to less than 40 hours, which saves the washing time of silica gel and improves the production efficiency of silica gel; magnetized water has high magnetism, and quickly washes out the salt ions in silica gel, thereby reducing the The amount of magnetized water reduces the production cost; the specific surface area of silica gel is 300‑800m 2 / g, the pore volume is 0.4‑1.0mL / g, which protects the fine pore structure inside the silica gel to the greatest extent and increases the proportion of micropores; the silica gel preparation method of the present invention not only has good economic benefits, but also has certain social benefits .