Based on vapor pressure spalling theory, the vapor pressure in self consolidating concrete(SCC) and fiber reinforced self consolidating concrete(FRSCC) was predicted using the one dimensional model of multi phase porous media. Vapor pressure induced spalling behavior of SCC and FRSCC was analyzed. In order to verify the validity of the proposed model, vapor pressure tests for SCC and FRSCC under fire were performed. Effects of steel fiber, micro polypropylene(PP) fiber, macro PP fiber and hybrid fiber on the relationship of vapor pressure time temperature were discussed. The results indicated that the addition of fibers can decrease the vapor pressure in SCC, delay the occurrence time of the peak value of pore pressure and can decrease the corresponding temperature at peak pressure. The pore pressure can be reduced by using micro PP fibers more effectively than by macro PP fibers. The significant factor for reduction of vapor pressure depends mainly on the number of PP fibers as well as on the fiber content. Compared to mono fiber, the use of hybrid fibers can further reduce the vapor pressure in SCC. Through comparison with the test results, it is found that the simulation model presented can well predict the build up of vapor pressure and fire spalling behavior of SCC and FRSCC.