The preparation of p-type heavily-doped 4H-SiC is conducted by using the laser irradiation of solid Al film. The effects of the Al film thickness and the laser pulse number on the doping results are analyzed and the control of different process parameters to the electrical properties of p-type doped layers is verified. The results show that the maximum carrier concentration is 6.613×10 17 cm -3, the minimum volume resistivity is 17.36 Ω·cm, and the doping concentration (particle number concentration) is 6.6×10 19 cm -3, when the Al film thickness is 120 nm and the pulse number is 50. The Al doping modification mechanism of 4H-SiC can be described as the formation of p-type doped layer as a result of the Si—C bond breaking and the replace of Si by Al under the ultraviolet laser irradiation.