The work aims to study mechanism of effects of laser de-painting on microstructure and properties of Ti17 alloy, and investigate whether laser cleaning can improve the microstructure and properties of substrate while removing pollutants. A layer of nearly 50 μm thick acrylic resin matte black paint was evenly sprayed on the surface of pretreated samples. De-painting processing was applied to the samples at different power with a pulsed fiber laser. Then three-dimensional morphology of the surface was observed with a white light interferometer surface contourgraph, microstructure with a metallographic microscope, surface microhardness with a microhardness tester, and surface roughness with a surface roughness meter. A large number of pits and white folds hardened layer appeared on the surface of the sample after laser de-painting. The microhardness of the surface was increased by about 5%. The surface roughness of the sample before and after laser cleaning changed little, at the sub-micron level. When the laser power is 15 W, the white hardened layer is evenly distributed with a thickness of about 10 μm, the maximum increase of surface microhardness is 6.9%, the surface roughness is 0.07 μm lower than the substrate, and the cleaning effect is better. Laser cleaning can improve surface properties of a substrate by selecting appropriate laser parameters while removing the pollutants.