The invention discloses a land-sea transferring method for a large-diameter steel cylinder. The land-sea transferring method comprises the steps that (1) steel cylinder segments are loaded on a vehicle and then transported to a wharf, thus transferring for the first time is completed; (2) after a steel cylinder segment transport ship is berthed, the steel cylinder segments are hoisted to be loaded on the ship; (3) after being berthed at a next wharf along with the steel cylinder segment transport ship, the steel cylinder segments are unloaded from the ship to be assembled into the steel cylinder; (4) a plurality of steel cylinder sea binding jig frames are arranged on a whole steel cylinder transport ship deck, and a ground bell is arranged in the position, around each sea binding jig frame, of the deck; and (5) the whole steel cylinder is loaded on the ship and fixed to the sea binding jig frames in the step (4), and thus transferring for the second time is completed. The transport safety of the steel cylinder and members can be improved significantly, and the technical guarantee is provided for further optimizing the construction period on the basis of reasonably allocating resources.