The purpose of this study was to evaluate the salt damage resistance of waterproofing membrane in order to protect the mortar or concrete substrate. Polyurethane and acrylic coating membrane were used, and the salt water immersion test and the chloride ion concentration test were carried out experimentally. Also, the salt damage in mortar was analyzed by comparing with the permeability of each specimens. Waterproofing membrane have a high salt damage resistance more than only non-coated substrate, and prevented the penetration of chloride ion from non-crack to 0.3mm-crack specimens in 13 weeks-accelerating test. Finally, the membrane thickness for suppressing salt damage was estimated from viewpoint of its permeability.