There are various methods for preparing electronic-grade silica sol, the most common of which include sol-gel method and ion exchange method. The sol-gel method prepares high-purity silica sol through a specific chemical reaction, while the ion exchange method removes impurities through ion exchange resin to obtain high-purity silica sol. A specific preparation method is to use silicon powder as raw material to prepare high-purity silica sol mother liquor under catalytic conditions, then select the particle size through a particle size selector, use ion exchange resin to remove impurities, and finally add a stabilizer to obtain electronic-grade silica sol. The silica sol prepared by this method has uniform particle size and high solid content, and is suitable for applications in a variety of high-tech fields.