In order to explore the influence of different cooling methods on laser machining, three different cooling methods of water, gas, and gas-water composite were used to assist laser processing of carbon fiber reinforced plastics. At the same time, the effect of different processing conditions on machining quality was studied by a single factor experiment, and the mechanism of different cooling methods was analyzed. The results show that the heated affected zone (HAZ) and groove depth decrease with the decrease of power and frequency and decrease with the increase of velocity. Under the same process parameters, the HAZ produced by gas-water-assisted laser processing is the smallest, followed by gas-assisted laser processing and the largest by water-assisted laser processing. When the laser power is 2250 W, the frequency is 1200 Hz, and the speed is 120 mm/s, the HAZ of water, gas, and water-gas composite cooling modes are 378 μm, 283 μm, 196 μm, respectively, and the groove depth is 401 μm, 789 μm, 647 μm, respectively. It can be seen from the comprehensive comparison that gas-water-assisted laser machining can achieve a better balance between heat and cold and obtain the best processing quality. This study provides a reference for better realization of low-damage machining of carbon fiber reinforced plastics.