Abstract: The finish machining of moulds remains a problem. Primarily, mould surface finish machining is achieved by handcraft with a very low speed ( normally is 10~30 min/cm² ), which occupies 30% of the whole procedure time. In order to increase polish efficiency laser polishing is applied. Laser polishing is a new polishing technology which a thin surface layer is molten and the surface tension leads to a material flow from the peaks to the valleys. In recent decades, laser-polishing has received much attention owing to many advantages that it possesses. Fiber laser has a lot of characteristics that suits for industrial-use, and so the laser-polishing techniques that was performed by fiber laser on continuous mode, were explored. With the method of orthogonal experimental design, several parameters including power, scanning velocity, scanning interval and focal-offset distance were optimized. Under the best parameters, the sample' s roughness made from 2316 tool steel is reduced from about R_a=1. 0μm to 0. 2μm.