The invention belongs to the field of polymer material and biomedical engineering, particularly relates to drug-loaded silica embolism microsphere and a preparation method thereof. Through technical improvement, silica microsphere is prepared into micron microsphere, hydrophilic polyethylene glycol coupling agent is coupled onto the surface of silica microsphere by efficient Huisgen cycloaddition reaction to form a neutral hydrophilic layer, so that the microspheres can be stably and uniformly dispersed in an aqueous medium to facilitate operation of arterial embolization; meanwhile, silica embolism microsphere has a nano porous structure which can adsorb chemicals, so as to reach the purpose of slow release of drug for treatment while achieving arterial embolization, which further improves the therapeutic effect. The embolism microsphere provided by the invention has good histocompatibility, is mainly used for arterial embolization treatment of diseases, especially suitable for arterial embolization treatment of hepatic tumor, and has broad application prospect.