The invention relates to a preparation method of a veneer decorative paper capable of purifying formaldehyde, and the veneer decorative paper. The preparation method comprises following steps: 1, urea-formaldehyde resin, modified starch, water-soluble chitosan, ethene diamine, borax, ammonium sulfate, and an osmotic agent are mixed so as to obtain a dipping rubber solution; 2, the dipping rubber solution is adopted for dipping treatment of decorative raw paper, the excess dipping rubber solution is removed via extrusion, and drying is carried out at a mixed atmosphere of dried air and ammoniagas until the water content of obtained dipped paper is 10% or lower; 3, terpolycyantoamino-formaldehyde resin, ZnO, a dispersant, ammonium sulfate, the osmotic agent, and a mold lubricant are mixed so as to obtain a coating rubber solution; 4, the surface of the obtained dipped paper is coated with the coating rubber solution, and then drying is carried out at the mixed atmosphere of dried air and ammonia gas until the water content of the coated paper is 7% or lower. The veneer decorative paper possesses excellent formaldehyde capturing and eliminating capacity; the formaldehyde release amount of surface decorated artificial board prepared from the veneer decorative paper is extremely low; the veneer decorative paper is suitable for interior decoration, is safe, and is friendly to the environment.