The invention relates to a hard asphalt granulation method and a device thereof. The method comprises the following steps: heating hard asphalt to a molten state, delivering the hard asphalt in the molten state to a distributing device capable of adjusting fluid falling speed, evenly distributing the hard asphalt onto a rotary steel belt in a dropwise state, and carrying out forced cooling on the steel belt with a cooling water spraying system arranged below the rotary steel belt, so that cured asphalt granules are separated and fall off from the steel belt at the rotary end of the rotary steel belt. The method has the advantages of simple technical process, low pressure grade, low operating cost, high production efficiency and small pollution, can conveniently adjust the size of the hard asphalt granules, and has strong adaptability to hard asphalts with different softening points (viscosities). The produced asphalt granules have the advantages of uniform size and beautiful appearance, do not directly contact the cooling medium, and can obviously reduce the smoke dust and water pollution in the production process.