Disclosed are a high temperature blasting resistance isotactic polybutene alloy and a preparation method thereof. The isotactic polybutene alloy of the present invention comprises 1-40% of isotactic polypropylene in parts by mass, 0.1-10% of a polypropylene-polybutene-1 block copolymer in parts by mass, 35-95.9% of isotactic polybutene-1 of a medium molecular weight in parts by mass, and 3-15% of isotactic polybutene-1 of a high molecular weight in parts by mass. The alloy material is prepared using a method of segmented polymerization of propylene polymerization, high hydrogen content butene polymerization and low hydrogen content butene polymerization. The prepared isotactic polybutene alloy has excellent high temperature blasting resistance and high temperature hydrostatic pressure, is high in vicat softening temperature, and is applicable to pressure pipes.