The work aims to solve the efficiency and quality problem of rapid continuous wave (CW) polishing of die steel surface. The CW laser Gaussian beam was converted into a flat-topped laser beam through a beam-shrinking mirror and a DOE diffraction shaper, so as to shape the CW laser beam and adjust the spot diameter. By optimizing the parameters of CW laser polishing process, the surface tension of molten pool was increased by combining scanning paths of zigzag pattern and square wave pattern while high laser scanning speed was maintained. The molten pool was promoted to flow around to make the peaks of microstructure generate material migration under the action of tension and flow to the valleys, thus achieving the purposes of filling peaks and valleys and reducing surface roughness. The flat-topped CW laser beam with a spot diameter of 470 μm was used to polish the die steel Cr12MoV with a combined scanning path of zigzag pattern and square wave pattern and a high-speed scanning speed of 500 mm/s. The original surface roughness Ra 1.942 μm could be rapidly reduced to Ra 0.26 μm through the detection of white light interferometer and SEM electron microscope and the polishing efficiency was 67% higher than that of traditional mechanical polishing, 94% higher than that of manual polishing and 125% higher than that of surface microhardness. Technological experiments show that the spot diameter of CW laser has a profound influence on the polishing surface quality. When CW laser is used to polish die steel surface, the laser processing parameters such as laser power, spot diameter, scanning speed, scanning route and step-over need to be optimized. On the premise of achieving the same quality effect, CW laser polishing efficiency is more than eight times that of the traditional mechanical polishing processes and more than 30 times that of skilled technicians‘ manual polishing. CW laser polishing can significantly improve the surface microhardness of die steel surface and is a kind of environment-friendly manufacturing technology without any pollution.