Abstract: The spalling behaviour and the temperature field distribution of RPC under high temperature were tested． The result showed that the spalling of RPC would occur when furnace temperate reached to 330 ℃ with the heating rate being 4. 8 ℃ /min． Before the explosion，the temperature differences were significant between the center and corner of specimens． The spalling critical temperature and time of RPC was analysed，and the calculation model of the spalling critical temperature and time as well as space was established． The results provided the scientific basis for the further quantificational calculation of the internal thermal stress in RPC，and the interpretation of spalling mechanism．