We practiced .thermal measurement outdoors using solar reflective materials that have the potential to suppress heat-island effect. Solar reflectance is calculated by heat balance in one case that samples are horizontal and the other case that samples are inclined so that the angle of incidence is almost normal incidence (about 7degree).We estimate that retroreflective components are 4 to 14 percent for bead-embedded type, 17 to 19 percent for capsule-lens type, and 23 to 30 percent for prism-array type.