The surface modification of PS films treated in aqueous hydrochloric solution by ozone aeration has been studied to enhance the interaction between PS and PVA films, and further to increase the survival rate of PS-PVA hollow microspheres. The halfquantitative analysis using FTIR spectra shows that the treatment in aqueous hydrochloric solution introduces carbonyl and hydroxyl groups onto the PS surface, and the contact angle measurements show that the surface of the treated PS film becomes hydrophilic. The strength of interaction between PS and PVA films before and after modification has been investigated by nanoindentation method, which shows an increase of 40% after treatment.