The invention discloses a preparation method for a metal part. The preparation method comprises the following steps that 1, metal powder is taken, added with an organic binder under the dark condition and uniformly mixed, then an antifoaming agent is added into the metal powder and uniformly mixed, and after bubbles fade away, surface impurities are removed, so that mixed slurry is obtained; 2, the mixed slurry is put into 3 D printing forming equipment to be printed layer by layer by utilizing controllable ultraviolet light beams, through the mode of surface exposure or spot scanning and according to a three-dimensional model of the part, and hence a metal part rough blank is prepared; 3, the metal part rough blank is subjected to low-temperature degreasing treatment, so that the organic binder in the rough blank evaporates and overflows; and 4, hot isostatic pressing treatment is conducted on the metal part rough blank, and therefore the compact metal part is obtained. According to the preparation method for the metal part, the principle of light curing rapid prototyping is adopted, the shape of the part is unrestrained, the process is simplified, the manufacturing cycle is shortened, and the product compactness is good.