The styrene-acrylic(St-BA-MAA/SDS-DNS86/H2O)emulsion modified by the ethyl-tetra-coordinated silicon was prepared,using water as the solvent,the laurel sodium sulfate and alkyl ethyl sulfuric acid sodium(SDS-DNS86) as the emulsifiers potassium per-sulfate(KPS) for the initiator and adding the initiator minute steps for free radical polymerization.The thermal properties analyzed by TG and the glass transition temperature determined by DSC were researched to the styrene-acrylic emulsion and emulsions modified by ethyl-tetra-coordinated silicon.The results indicated that the thermal properties of the modified membrane increas and the glass transition temperature of the modified membrane decreases and adhesion force of the modified membrane enhances.