The composition including porous silica particles according to the present invention may effectively deliver a bioactive material to target tissues or cells in the blood stream by modifying surfaces of the particles to inhibit aggregation and precipitation in the blood. In addition to the above advantage, the embolic composition including porous silica particles according to the present invention has advantages of having specific physical properties such as biodegradability and sustained release thus to achieve excellent embolization effects and targetability toward target tumor tissues or cells, thereby reducing side effects.