The invention discloses a high isotactic polypropylene alloy material and a preparation method thereof. The material contains 5-98.9 parts by weight of polybutylene, 1-80 parts by weight of polypropylene and 0.1-15 parts by weight of propylene-butene copolymer; the isotacticity of the high isotactic polypropylene is larger than 85%, and the smelting point of the high isotatic polypropylene is 115-129 DEG C; the isotacticity of the high isotactic polypropylene is larger than 85%, and the smelting point of the high isotactic polypropylene is 155-169 DEG C; the propylene-butene copolymer contains a random copolymer and a segmented copolymer of propylene-butene. The preparation method uses a titanium/vanadium supported catalyst and adopts a multistage sequential polymerization manner and specifically comprises the steps of carrying out propylene polymerization or butane-1 polymerization, then initiating butane-1 polymerization or propylene polymerization, and respectively carrying out propylene polymerization or butane-1 polymerization, and so on to synthesize the high isotactic polypropylene alloy material. The material is a powdery or spherical product, and has the advantages of excellent impact resistance, thermal creep resistance and low shrinking percentage of polybutylene, high modulus, high surface hardness and fast setting of polypropylene, and the like.