The invention discloses a dike-striding transfer method for a large-tonnage steel beam, and relates to the field of bridge construction. The method is used for transferring the steel beam to pass through a dike. The method comprises the following steps: step 1: constructing transfer platforms connected with the dike and same in height on two sides of the dike; step 2: lifting the steel beam to the transfer platform on one side of the dike by a lifting device; and step 3: transporting the steel beam to the transfer platform on the other side of the dike by a transport device. Therefore, the problem in dike-striding transfer of the steel beam is effectively solved and the transfer efficiency is high.