Abstract: In order to investigate the electronic properties of 4H-SiC crystal under high power laser irradiation, the first principles with pseudo potential method based on density functional perturbation theory was applied to theoretically analyze and experimentally verify the electronic properties of wurtzite 4H-SiC crystal under the strong laser irradiation. The results indicate that 4H-SiC remains semiconductor with indirect band-gap in the range of 0eV~2.75eV. When the electronic temperature reaches above 3.0eV, the crystal turns to be semiconductor with direct band-gap. The forbidden bandwidth increases with the rising of T_e in the range of 0eV and 2.0eV, and the forbidden bandwidth quickly reduces with the rising of T_e in the range of 2.0eV~3.5eV. When T_e is over 3.5eV, the gap has disappeared and metallic properties are presented. The study will be helpful for making special function electronic components of 4H-SiC crystal.