The instant disclosure provides a thermal-curable adhesive composition and adhesive sheet. The thermal-curable adhesive composition has a rate of change of adhesion ranging from 80% to 98% and defined by the following equation: V=[(V0−V1)/V0]×100, wherein V is the rate of change of adhesion of the thermal-curable adhesive composition, V0 is the adhesion of the thermal-curable adhesive composition under room temperature, and V1 is the adhesion of the thermal-curable adhesive composition after being heated to a predetermined temperature then cooled to the room temperature.