Abstract: A new magnetic mesoporous silica nano material was synthesized by using improved Stober and solvothermal methods with formic acid solution as acidic medium and PEG-PLA as template.X-ray diffraction (XRD),field emission scanning electron microscopy (FE-SEM),transmission electron microscopy (TEM),physical property measurement system (PPMS),and specific surface area and pore size distribution measuring instrument were applied to characterize this material.The results showed that the magnetic mesoporous silica nano material which was synthesized in 0.2 mol/L formic acid solution had 8.2 nm of pore cavities,258 m²/g of surface area,0.32 cm³/g of pore volume and 53 A·m²/kg of saturation magnetization.This magnetic mesoporous silica nano material had favorable adsorption capacity of bovine serumalbumin,toluylene red and methylene blue with 53.6,24.1,66.8 mg/g respectively,which indicated it had certain application prospect in the separation and enrichment complex aspects of environmental samples.