Using a 1064-nm picosecond fiber laser, five different energy densities were designed to conduct laser cleaning experiments on oil and rust stains present on H13 hot die steel. The results show that energy densities of 2 J/cm² and 3 J/cm² have the best cleaning effect; the surface roughness R_a can reach (1.1 ± 0.3) μm and (1.5 ± 0.5) μm, respectively; and the surface hardness increases to (256 ± 3.8) HV and (256 ± 2.9) HV, respectively. The main phases after cleaning are VC, (Mo, Cr)₆C, (Cr, Fe)₇C₃, and (V, Cr)₂C. In addition, the EDS results show that the contents of C, Mo, V, and Cr on the mold surface are increased.