Mesoporous magnetic composite carbon spheres were prepared by in-situ polymerization using tetraethyl orthosilicate (TEOS) as the silicon precursor under the assistance of surfactant cetyltrimethyl ammonium bromide (CTAB).The effects of ethanol-water ratio (Vethanol:Vwater), CTAB dosage and hydrothermal tem-perature (HT) on morphology, particle size and surface structure of carbon spheres were investigated. TEM, SEM, BET and VSM were used to characterize and analyze of carbon spheres. The results show that the ethanol-water ratio and surfactant significantly affect the morphology and particle size of the carbon spheres. In addition, the hydrothermal temperature can change the pore structure of the carbon spheres. The specific surface area of the mesoporous magnetic composite carbon spheres prepared under optimized conditions of Vethanol:Vwater=3:4, CTAB=0.6g, HT=100℃is 553m2/g, which is 2.7 times higher than that before the introduction of the silicon precursor. Moreover mesoporous pore volume ratio in-creased from 18% to 83%. At the same time, the adsorption properties of the material on erythromycin was investigated, and the saturated adsorption capacity was 255mg/g. The adsorbed material was regen-erated with n-butyl acetate, and the adsorption amount was maintain at over 85% of the initial adsorption amount after five cycles of regeneration.