The severe erosion in the bicomponent propellant heat sink thrust chamber of hydrogen peroxide and kerosene through the firing test is studied. As shown in the results of CT scanning, the copper lining is burned through to expose a large gap between the copper lining and the stainless-steel shell. The erosion area of cross-section of copper lining decreases as the distance from the chamber head along the axial direction increases. During the firing test, the color of flame changes to green at 6.78s and after 9.34s the flame continues to be green. The temperature of the flame is obviously higher than that of normal combustion flame. It is considered as the flame color reaction of copper. The temperature of the burning gas reaches about 2640 K. Therefore, there is a phase change of copper lining, i.e., the loss of liquid copper on the surface under short-time operating conditions. Due to incomplete catalysis, the liquid hydrogen peroxide accumulates in the combustion chamber and is catalyzed by pure copper. It will cause the inner wall to be burned through to expose a hole. Thus, it is significant to adopt a catalytic bed of fast response and high efficiency, optimize the time sequence of pulse test, and select the compatible materials instead of copper for the chamber lining, for the purpose of improving the stability of heat sink thrust chamber. This paper is designed to break through the key technology of multiple starts and long-time operating conditions of hydrogen peroxide/kerosene bipropellant engine.