The invention discloses a polybutene alloy material and a preparation method thereof, and belongs to the field of polyolefin material, specifically relates to a polybutene alloy material and a preparation method thereof. The polybutene alloy material provided by the present invention comprises, by mass, 50-99% of poly-1-butene, 1-40% of polypropylene and 0-10% of a butane-propylene copolymer. Thepreparation method is characterized by: adopting a TiCl4/MgCl2 supported titanium catalyst for synthesis of the polybutene alloy material through a two-phase polymerization method. The polybutene alloy material provided by the present invention has a core-shell structure, and has advantages of the combination of the excellent impact resistance of the poly-1-butene, the heat resistance and creep property of the poly-1-butene, the low shrinkage rate of the poly-1-butene, the high modulus of the polypropylene, the high surface hardness of the polypropylene, the rapid shaping of the polypropylene, and the like, such that the polybutene alloy material can replace the partial use of the poly-1-butene and the polypropylene. In addition, the polybutene alloy material can be applicable for preparation of the pipe and the pipe fitting, toughening modification of the polypropylene, or the polybutene alloy material can be used as the general polyolefin material.