Sandwich structures made of carbon fiber reinforced plastics (CFRP) have high utility characteristics such as lightweight, high stiffness, and low coefficient of thermal expansion.Therefore, CFRP is one of the attractive candidates as structural material in aerospace field.Today, the use of satellite at high temperature environment such as exploration in Venus etc is under schedule.However, the heat resistance of resins used for present CFRP sandwich panels is pretty low.The purpose of this study is the estimation of high-temperature property of new sandwich panels developed to improve thermal resistance.