The invention belongs to the technical field of plastic processing, and concretely relates to a polypropylene composition and a preparation method thereof. The polypropylene composition comprises 100 parts of polypropylene, 0.15 parts of an antioxidant, 0.04 parts of a lubricant, 0.05 parts of an acid absorption agent and 0.06 parts of a nucleating agent. The polypropylene composition has high fluidity and good processing stability, is suitable for thin-walled injection molding and large complex product production, can be used multiple times, and has good economical property; and the preparation method is simple, is easy to implement, and is easy to realize.