The utility model provides a novel extra-strong steel core aluminium alloy wire used for extra-high voltage and long span. The wire comprises a steel core formed by 37 galvanized steel wires, an aluminium layer including 48 aluminium alloy single wires surrounding the steel core. Each galvanized steel wire is a steel wire whose 1% extension stress is higher than or equal to 1670 megapascal and extension strength of the galvanized steel wire before stranding is higher than or equal to 2050 megapascal. The novel extra-strong steel core aluminium alloy wire used for extra-high voltage and long span in an embodiment comprises the steel core formed by 37 galvanized steel wires and the aluminium layer including 48 aluminium alloy single wires surrounding the steel core, and 1% extension stress of each galvanized steel wire in the steel core is higher than or equal to 1670 megapascal and extension strength of the galvanized steel wire before stranding is higher than or equal to 2050 megapascal. Thus, 1% extension stress and extension strength of the formed wire is higher than or equal to those of an existing wire, thereby improving usability of the wire in long-span power transmission application.