IR thermal imaging system is used to measure the front and rear surface temperature distribution of the coated metal (30CrMnSiA steel and LF6M alloy) irradiated by repetitive frequency (RF) laser. The characteristics of temperature increasement with laser irradiation time are analyzed in this paper. The experiment results show that the rear surface temperature of metal is mainly dependent on laser average power when target thickness is more than 1.6mm. The higher the laser pulse frequency is, the higher the efficiency of laser heating metal has. RF laser heating material is better than CW laser does．