The invention discloses a method for toughening and modifying polypropylene. According to the invention, components, component parts and processing characteristics of the method are as follows: a, stoving polypropylene (PP), polyolyaltha olfin (POE), ultra-high molecular weight polyethylene (UHMWPE) and linear low-density polyethylene (LLDPE) resin at the temperature of 60-80 DEG C, and completing mixing in a high-speed mixer at a mass ratio of PP:POE:UHMWPE:LLDPE=100:(3-25):(2-15):(5-20) to obtain a raw material A; b, adding a stabilizing agent and a lubricant in the raw material A at the mass ratio of polypropylene: stabilizing agent: lubricant=100:0.2:1, and conducting high-speed stirring and mixing to obtain a raw material B; c, conducting twin-screw extrusion on the raw material B, and controlling a processing section temperature within 160-210 DEG C and a screw rotating speed within 120-180 rmp to obtain the toughened and modified polypropylene, wherein the cantilever beam impact strength can be improved by 13 times maximally, and the descend range of the tensile yield strength is no more than 12%.