The invention relates to a polypropylene composition, and concretely relates to a highly-transparent, heatproof and impact-resistant polypropylene composition and a preparation method thereof. The polypropylene composition is prepared by adopting random copolymerized polypropylene resin as base resin and adding metallocene linear low density polyethylene, a nucleating agent, aluminum oxide and assistants. The assistants comprise an antioxidant, an antistatic agents and an acid acceptor. The melt mass flow rate of the random copolymerized polypropylene resin is (10-40)g/10min, the melting temperature range of the random copolymerized polypropylene resin is 150-170 DEG C, and the ethylene mass percentage content is 3.5-5.5%; and the melt mass flow rate of the metallocene linear low density polyethylene is to (1-30)g/10min, and the density is 0.912-0.930 g/cm<3>. The polypropylene composition improves the transparency of the polypropylene resin, and has the advantages of high impact resistance, good heatproof property, good anti-oxidation property and long service life. The invention also provides the preparation method of the polypropylene composition.