An exhaust process of heat-sensitive fusible metal and pressure-sensitive metal diaphragm under slow cook-off conditions of melt-cast explosive was studied by using a cook-off device with exhaust release structure. The results show that the preset venting hole can smoothly remove the gas generated by thermal decomposition, slow down the pressure increase in the bomb body, and effectively reduce the violent of the charge reaction; when the venting hole is sealed by the fusible metal, the fusible metal gradually softens and breaks during the phase change of the explosive, forming a pressure relief channel, and the exhaust process is relatively gentle; when the venting hole is sealed by the pressure sensitive diaphragm, the pressure inside the bomb increases to the diaphragm damage threshold, the diaphragm will undergo impact-shear failure, the explosive is ejected and the combustion reaction occurs.