The invention relates to a preparation method of a silica gel carrier for loading a catalyst. Silicate and an inorganic acid are adopted as raw materials, a pore-enlarging agent alkaline medium is used as a base liquid, the silicate gel carrier is modified through a process for simultaneously generating a silica sol and hydrotalcite; and an aqueous solution of the inorganic acid is added in a gelreaction to adjust the pH value of the reaction solution, and a high-temperature hydrothermal reaction is carried out to prepare the silica gel. The method can greatly improve the specific surface area of the silica gel without affecting the pore volume of the silica gel, so the basic physical properties of the silica gel carrier are improved.