A waterproofing membrane is partially fixed to a substrate by fasteners in mechanically anchored systems. For designing a safer anchored waterproofing system against typhoons, it is needed to make clear the behavior of it under strong wind. Two kinds of full size specimens with a parapet and without one were exposed to high wind speed of a wind tunnel. The behavior of the system was investigated from the three aspects such as wind forces to a membrane, deformation of a membrane and tensile forces of fasteners induced by high wind. Strong wind force was observed in the area close to the windward edge for the roof without a parapet and about 1m on the leeward from a parapet for the roof with a parapet. The membrane was lifted up by wind to about 60mm in maximum height and was extended to about 0.6% in maximum elongation and it oscillated about 5-20Hz in periodic time. The tensile force of more than 160N was observed in some fasteners, depending on the location in the roof.