In order to enhance and toughen the polymer resin with hollow glass microspheres(HGM), polyurethane coating modification was carried out on HGM. The paper aims to explore the conditions and formulas of the physical coating and chemical coating. The physical method is to dissolve thermoplastic polyurethane elastomer in solvent and add HGM to prepare samples. In chemical method, HGM, alcohol component, and isocyanate component are added into solvent, and polymerization reaction is carried out under appropriate conditions to obtain samples. The coating effects and whether there was adhesion between the microspheres were observed through an optical microscope. The results showed that the polyurethane concentration of 4% was suitable for physical method. The reaction temperature of 80 ℃ is suitable for chemical method. The product synthesized by infrared spectroscopy was polyurethane, and the reaction time was 120 min according to the observation results of optical microscope. The effects of glycerol and toluene-2,4-diisocyanate(TDI) dosage on the thickness of the coating layer were explored through thermogravimetric analysis and optical microscope. This study provides a reference for the preparation of polyurethane-coated HGM 'soft-coated hard' core-shell structure, so that it can be used as a modifier to improve the comprehensive properties of resin.