Method for preparing multi-nanopore oxidation film on surface of molten nickel-titanium implant on laser powder bed

The invention discloses a chemical polishing method for additive manufacturing of a nickel-titanium alloy implant, which comprises the following steps: S1, preparing a chemical polishing solution which comprises nitric acid with the concentration of 1-8 mol/L, hydrofluoric acid with the concentration of 1-22.5 mol/L and deionized water, and uniformly mixing the chemical polishing solution with the nitric acid with the concentration of 1-8 mol/L, the hydrofluoric acid with the concentration of 1-22.5 mol/L and the deionized water; s2, the chemical polishing solution is placed in a polyethylene plastic beaker, and the polyethylene plastic beaker is placed in a magnetic stirring ice-water bath pot; s3, a nickel-titanium alloy complex structure support is tied and hung in the middle of a polyethylene plastic beaker containing the chemical polishing solution through a polyethylene line, and the polyethylene line is tied to the support; s4, the rotating speed of the magnetic stirring rotor is set to be 50-300 r/min