The evolution of surface morphology after nanosecond laser polishing of inclined surfaces and the influence of surface inclination on polishing results are investigated, which may provide a reference for laser polishing of free form surfaces in additive manufacturing. A nanosecond laser is used to laser polish rough surfaces that are not perpendicular to the optical axis, and the surface morphology after laser polishing is measured and analyzed using a laser confocal microscope. The results show that when the surface is tilted at 30°, there is an abnormal increase in surface profile fluctuations on the polished surface near 4 mm from the starting point, and the surface roughness value increases to 15.80 μm. When the inclination angle increases to 45°, the position where the surface profile fluctuation abnormally increases changes to around 2 mm. When the inclination angle is 60°, there is no abnormal increase in surface profile fluctuations. The abnormal increase in surface profile fluctuations reflects the transition process of laser polishing from over melt polishing to shallow melt polishing. The laser polishing process for free-form surfaces requires selecting appropriate laser power density and defocus amount based on the inclination and surface roughness of the polishing area, in order to achieve good laser polishing quality.