The invention provides a preparation process of a titanium dioxide containing double-wavelength light absorption water-based anti-forgery ink additive. The preparation process comprises the following steps of: ultrasonically dispersing nanometer titanium dioxide, de-ionized water, and a surfactant uniformly to obtain a nanometer titanium dioxide solution; mixing a solution of polystyrolsulfon acid doped polyethylenedioxythiophene with the solid content of 1.3-1.7% with de-ionized water, adding a negative ion surfactant into the resulting mixed solution, and ultrasonically dispersing the resulting solution uniformly to obtain a solution A; mixing the titanium dioxide solution with the solution A to obtain a mixed solution B; and heating the mixed solution B to 40-70 DEG C, adding an alcoholic solvent and powder with powder diameter of 200-1000nm into the mixed solution B under a stirring condition, and finally obtaining the titanium dioxide containing double-wavelength light absorption water-based anti-forgery ink additive after reacting for 40-60 minutes. The anti-forgery ink additive has light absorption effect within a 1000-1200nm infrared band and a 240-300nm ultraviolet band, and can be used as the water-based anti-forgery ink additive.