Nickel-based superalloy GH3536 is a preferred material in the aerospace industry due to its high corrosion resistance, oxidation resistance, high-temperature resistance, and excellent processability. However, its surface polishing still remains a serious challenge. Traditional techniques such as electrochemical polishing are unable to achieve non-damage mirror processing, and the used electrolyte pollutes the environment. This study aims to investigate the removal mechanism of chemical-mechanical polishing (CMP) for GH3536 nickel-based alloy in different composition solutions to obtain a flawless 3D-printed ultra-smooth mirror. The CMP was studied by a single-factor test. Electrochemical test technology and X-ray photoelectron spectroscopy were applied to find out the rate of reaction and the valence state of the surface in the CMP process. This helped to figure out the specific corrosion process and complexation reaction. It found out how fast the passivation film formed and how quickly it was removed from the alloy‘s surface by looking at how the corrosion potential and current changed over time in the polishing liquid. The ways the chemical makeup of the polishing liquid affected the surface of the material were also found. The elemental composition and electronic state of the surface of the 3D-printed nickel-based alloy GH3536 were measured. The surface morphology of the nickel-based alloy was observed by an ultra-depth microscope and a Zeiss field emission scanning electron microscope. The Material Removal Rate (MRR) of the alloy was calculated by precision balance, and the roughness change of the alloy was measured by an optical 3D surface profiler. The material removal rate and surface roughness were used to characterize nickel-based alloys. The material removal rate of GH3536 decreased with the increase of PH value and increased with the increase of oxidant concentration during CMP processing. Surface roughness decreased first and then increased with the increase in PH value and oxidizer concentration. The results showed that when the PH value was 3-3.5 and H2O2 concentration was 10%, the optimal material removal rate and surface roughness (Ra was 0.684 nm and Sa was 1.699 nm) could be obtained, and the CMP polishing surface could achieve an ultra-smooth and low-damage mirror effect, which could be used for ultra-precision machining of nickel-based alloys with high profile accuracy. The chemical reaction equation was established based on the electrochemical and XPS measurements. It was determined that the surface of nickel-based alloy GH3536 was first oxidized into oxides such as Ni and Fe during the CMP process and then formed polyvalent ions such as Ni and Fe under the action of acidic H+. Finally, the complex reaction with citric acid was carried away from the surface or mechanically removed. In conclusion, the 3D printed nickel-based alloy GH3536 processed by CMP has lower surface roughness and better surface morphology than that after conventional electrochemical machining, which can be used for ultra-precision machining of nickel-based alloys with high requirements for face shape accuracy. And the material removal mechanism of nickel-based alloy GH3536 is effectively revealed based on electrochemical technology and XPS depth profiling, and the laws of different pH values, oxidizer concentrations and different polishing liquid slurries on the material removal mechanism are obtained. It provides guidance for obtaining new 3D printing alloy materials with high quality surfaces.