There are a huge demand for fast and efficient demolition workers in rescue operations. Laser cutting showed great potential because of its characteristics of non-contact, high speed, and high precision. In order to explore the application of laser cutting technology in the rescue and demolition of Q235 steel plate, taking 8 mm and 15 mm thick Q235 steel plate as the research object, the high-power fiber laser was used for long-distance cutting experiment. The theoretical analysis and experiment verified the influence of laser power and cutting speed on the cutting quality. The results show that, for 8 mm thick steel plate, the optimal cutting effect can be obtained when the distance between the laser head and the workpiece is 10 m, the cutting speed is 2.00 mm/s, and the laser power is 10 kW, respectively; for 15 mm thick steel plate, the distance between the laser head and the workpiece is 13 m, the cutting speed is 2.25 mm/s, and the laser power is 13 kW. The hardness test results also reveal the influence of laser power on the hardness of the material after cutting, indicating that laser cutting not only changed the geometry of the material, but also may affect its mechanical properties. This result is helpful for the laser cutting technology in the field of rescue and demolition, and provides optimized process parameters for practical application.