Abstract: The laser cleaning technology was used to clean contaminants on the surface of TC4 titanium alloy. The effects of pulse width on the macromorphology, micromorphology, three-dimensional morphology, chemical composition and surface flatness of the titanium alloy were studied. The results show that when the pulse width is 150 ps, the macrosurface of titanium alloy is uniform and bright, and the microstructure is similar to the original sample. In addition, the oxygen content on the surface of the sample decreases, and the roughness is relatively small, the roughness is better. When the pulse width increases to 1ns and 5 ns, secondary oxidation occurs on the surface of the sample, and oxygen content increases to some extent. A large number of molten pool morphology could be observed on the surface of the sample. The pool is recessed in the center and raised on all sides, and arranged regularly with an overlap rate of about 80%, forming the laser cleaning pattern visible to the naked eye macroscopic. The larger the pulse width, the larger the surface roughness and the worse the flatness.