Polypropylene composition and preparation method thereof, and stretched film prepared from polypropylene composition

The present invention provides a polypropylene composition for preparing a stretched film, and the stretched film. The polypropylene composition comprises, by weight, (A) 100 parts of a propylene polymer composition, and (B) 0.01-1 part of a nucleating agent, wherein the component (A) is a propylene homopolymer having high stereoregularity and high melt strength, a melt index (190 DEG C/2.16 kg) of the component (A) is 1.0-10 g/min, molecular weight distribution Mw/Mn of the component (A) is 6-20, the content of the molecules having a molecular weight of more than 5000000 is more than or equal to 0.8 wt%, Mz+1/Mn of the component (A) is more than or equal to 70, and the component (B) is at least one selected from a sorbitol nucleating agent or an aryl phosphate nucleating agent. The obtained film prepared from the polypropylene composition has characteristics of excellent high temperature tension property, good rigidity, low haze and high gloss, and shows strong competitiveness when the film is used for preparing thinning BOPP films.