PVA fiber has been used as a cement reinforcement because of its good mechanical properties and outstand-ing chemical resistance. However, excessively high interfacial adhesion between PVA fiber and cement matrix induced the fast fiber failure by stress localization at the interface. In the study, thus, we tried to modify the surface of PVA fiber by heat treatment in order to decrease the interfacial adhesion strength. Heat treatment temperature and time were varied to obtain the optimum condition for the modification. To exemine the fiber surface and interfacial conditions, various analyses were carried out including SEM, TGA, ATR, XPS, tensile properties and contact angle measurement. The interfacial shear strength between fiber and cement matrix was measured by a fiber pull-out test. The results showed that the wettability of the PVA fiber was lowered and interfacial strength was decreased by heat treatment, because OH groups of the PVA fiber were reduced.