A method of drying high-level radioactive wastes and device thereof contains a suspension mechanism for hanging a manual elevating mechanism, and a shielding cover. The manual elevating mechanism couples with a basket for accommodating wastes by using a hanging rope, and the shielding cover is fixed below the suspension mechanism and in a moving path of the basket. The basket is moved to a storage tank containing water in which radioactive wastes are stored, and the radioactive wastes are pumped into the basket by means of a pump. The basket is then lifted above a water surface of the storage tank and received in the shielding cover, and then the shielding cover is moved into a water holder so as to drain waters in the basket. The basket is further moved onto a heating seat to be heated and a vacuum equipment is started to dry the radioactive wastes.