Polypropylene composition with high fluidity and high dimensional stability and preparation method thereof

The invention discloses polypropylene composition with high fluidity and high dimensional stability and a preparation method thereof. The polypropylene composition with high fluidity and high dimensional stability comprises components in parts by weight as follows: 10-60 parts of homo-polypropylene, 10-40 parts of co-polypropylene, 10-25 parts of thermoplastic elastomer, 3-8 parts of polyethylene, 0-35 parts of mineral fillers, 0.2-1 part of a heat stabilizer, 0.2-1 part of a light stabilizer, 0.3-1 part of a coupling agent and 0.5-3 parts of other auxiliaries. The preparation method comprises the steps as follows: raw materials are weighed in the ratio in parts by weight; the raw materials are stirred and mixed for 2-8 min at a low speed to obtain a premixed material; and the premixed material is added into a double-screw extruder for melt blending and extruding granulation. According to the invention, a product has high fluidity, low shrinking percentage and good dimensional stability; and a production formula is mature, an extrusion process is simple, the product performance can be regulated according to the formula and is controllable, and an injection molding process has a wide range.