As a very popular metal surface cleaning process nowadays, Laser de-rusting is great development prospect in the field of rust removal on the surface of HT200. A 1 064 nm wavelength of pulsed fiber laser have been investigated in this experiment, the influence of laser power, laser frequency, scanning speed and scanning times on rust removing effects have been studied by the by the mechanism and model of laser de-rusting in this article. The good effect of laser de-rusting was demonstrated by observing the content of elements on the surface of HT200 and scanning electron microscope observation after cleaning. Hardness and surface roughness measurements show that hardening occurs on the surface of HT200 under the action of laser, and the surface of HT200 reaches the standard of finishing, and the cleaning grade reaches Sa 2.5, thus achieving the ideal laser cleaning effect.