Polypropylene composition and preparation method thereof

The invention relates to a polypropylene composition with favorable rigidity-toughness balance and coating performance and a preparation method of the polypropylene composition. An inorganic filling material and a coupling agent are put into a mixing machine to be uniformly mixed, and then polypropylene resin, high-fluidity anti-impact co-polypropylene resin, a toughening agent, a coating modifying agent, a lubricant, an antioxygen and a photostabilizer are added and are uniformly mixed to obtain a mixture; and finally the mixture is melted, blended, extruded and pelletized to obtain the polypropylene composition. The polypropylene composition comprises the following components by mass percent: 40 to 80 percent of polypropylene resin, 0 to 40 percent of high-fluidity anti-impact co-polypropylene resin, 10 to 25 percent of toughening agent, 5 to 20 percent of inorganic filling material, 2 to 10 percent of coating modifying agent, 0.1 to 1 percent of coupling agent, 0 to 2 percent of lubricant, 0.1 to 1 percent of antioxygen and 0.1 to 1 percent of photostabilizer. The polypropylene composition has favorable rigidity-toughness balance, fluidity and coating performance and can be used for manufacturing automobile bumpers, household appliances and the like.