To dissipate heat for reducing or preventing excessive perspiration or discomfort caused by heat when used.

A composite material used in an elastic orthosis includes a center layer 110, an inner layer 130, and an outer layer 120. The center layer, having a plurality of grooves which are crossed to each other, is formed with a lattice pattern functioning as a path, along the width and length of the center layer, thus promoting heat dissipation and moisture dissipation of a body part. A plurality of cuts 150 are extended through the whole depth of the center layer, and arranged to cross the surface area of the center layer to further have sufficient elasticity and density for imparting a suitable compressive support. In another embodiment, the center layer has a plurality of arc slits 250 for defining a tub site 255 which is fitted to the center layer.