This paper aims to prepare high-performance organic-inorganic composite coatings with silica sol and styrene- acrylic emulsion as the main raw materials, and to provide some valuable reference for its application. Three kinds of silane coupling agents, KH550, KH560 and KH570, were used to graft modified silica sol in turn. The silica sol with better modified effect was selected to prepare four kinds of composite coatings with modified silica sol mass of 0%, 35%, 70% and 105% (relative to the mass fraction of styrene acrylic emulsion). The modified effect of silica sol were characterized with Fourier transform infrared spectrometer, Zeta potentiometer and scanning electron microscope (SEM). The heat-insulating and energy-saving properties, mechanical properties and micro morphology of the four coatings were characterized by using ultraviolet/visible/near- infrared spectrophotometer, multi-functional materials surface performance tester and scanning electron microscope (SEM). KH560 has the best graft modification effect on alkaline silica sol. Adding a certain amount of modified silica sol to styrene- acrylic emulsion can significantly improve the performance of the coating. When the additive amount of modified silica sol is 70% of the weight of styrene-acrylic emulsion, the comprehensive performance of the coating is the best, the solar reflection ratio and near-infrared reflection ratio of the coating are 0.683 and 0.624, the adhesion of the coating is 3.85 MPa, the mass loss rate after 1000 rings of wear is 53%, the tensile strength is 5.4 MPa, but the fracture elongation is reduced significantly, only 49.8%. KH560 is more suitable for the grafting modification of alkaline silica sol, and the mechanical properties, heat-insulating and energy-saving properties of styrene-acrylic emulsion coating is significantly improved after adding KH560 modified silica sol. In practical use, it is suggested that the additive amount of modified silica sol is 70% of the mass of styrene- acrylic emulsion.