Abstract: At Minami-daitou Fishing Port, windbreak walls are constructed around the fishing port to alleviate strong wind, by using excavated materials. The observation study of wind and windblown salt is carried out in winter and typhoon seasons to examine the effects of the windbreak wall and shelterbelts.The energy distributions in strong wind from the north show that wind velocity behind the windbreak wall is considerably weaken. Meanwhile, wind direction is irregularly changed along the windbreak wall. And in case of strong wind from the north, the density of wind-blown salt behind the windbreak wall is approximately one tenth compared with that at the coastal area.As for the reuse of the future excavating materials to expand the basins, numerical simulation is to be conducted in order to determine appropriate scale and layout of windbreak wall on the basis of observation results.