In order to reveal the mechanism of energy absorption and transfer of materials in laser cutting of carbon fiber reinforced plastics (CFRP), a three dimensional finite element model for parallel laser cutting of single-fiber arranged CERP, a three dimensional fiber-spot diameter ratio model and a three dimensional fiber-resin double phase model are established, respectively. Numerical simulation results show that, with the decline of fiber-spot diameter ratio, the kerf width decreases from 229.45 μm to 95.60 μm, while the width of the heat affected zone (HAZ) decreases from 172.08 μm to 156.79 μm. The experimental results agree well with the simulation results, and the errors for the kerf width and the HAZ width are 5.97% and 1.13%, respectively.