The invention discloses a method for preparing grafted PP (polypropylene)by a two-component melt-grafting method. The method comprises the following steps: adding 40 to 100 weight parts of PP, 20 to 50 weight parts of polyamide, 1 to 30 weight parts of bulking agent, 0.1 to 5 weight parts of antioxidant and 0.1 to 3 weight parts of lubricating agent into a high-speed mixer, regulating the rotating speed to be 50 to 60 r/min and the temperature to be 180 to 200 DEG C, and mixing for 5 minutes; extruding the mixed mixture by using a twin-screw extruder, and granulating, wherein the extruding temperature is 170 to 210 DFEG C. According to the method, by graft modification on the PP, the compatibility between the PP and other polymers is improved, various defects of the PP caused by non-polarity of macromolecules are overcome, and the chromaticity, the adhesion performance, the antistatic property, the mechanical performance and the like are improved. Through the method, the material with high rigidity and toughness and high spraying performance can be obtained.