By changing the repetition rate, energy-flux density of focusing spot and scanning speed of a femtosecond laser, the effect of laser processing parameters on the removal rate of a diamond coating was investigated. Based on the observation results by the white-light interferometer combined with the numerical fitting method, the material removal rate function model was established. The analysis of experimental results shows that the accumulated laser energy within the coating surface per unit time remained stable at different repetition rates, and the material removal rate did not change significantly. The ablation intensity as well as the material removal rate raises with the increase of energy-flux density of focusing spot. The processing results under different laser scanning speeds are different, and the material removal rates exhibit a variance trend of first increasing and then decreasing with the increase of scanning speed.