Effects of hydrogen peroxide and inhibitors (sodium benzoate, NaNO3, sodium lauryl sulfate) on material removal at low down pressure for chemical mechanical planarization of Al alloy were investigated in alkaline slurry by using atomic force microscope, electrochemical polarization tests, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The material removal rate initially increases with concentration of H2O2 owing to the increase in corrosion potential and in thickness of oxidization layer, and then reaches a constant value. Additionally, surface scratch and orange peel disappear with H2O2. Sodium lauryl sulfate (SLS) reduces the surface roughness while maintaining a reasonable material removal rate in comparison with sodium benzoate and NaNO3 due to decrease in passive current density and increase in thickness of passive layer. A weak passive layer is generated on Al alloy surface by adhesive of SLS with H2O2, which is easily removed at low mechanical abrasion. The chemical composition of the film layer is dominated by the Al oxide rather than sulfate though the thickness of the passive layer is increased with SLS concentration.