This study was determined for identifying the characteristics of green wall system using moss. In here, the authors discussed moss’ thermal characteristics and effect of heat-island in depth. The authors was conducted two experiment for collecting empirical data, thermal performance measurement of moss-wall using sensors and thermal image with thermal camera. This study showed that 1) Moss panel is effective for heat-island effect. In analysis of thermal camera, surface temperature of moss panel is lower than other materials consisting building’s elevation. 2) Moss panels is not useful for improving thermal performance. The temperature difference of indoor and outdoor by three wall system including moss wall does not have significance. just 1 or 2˚C. Therfore, moss-wall system is possible to efficient to heat-island effect, but it does not relate with thermal performance.