The invention discloses a transformer-used rare earth boron copper alloy transposed conductor and a manufacturing method thereof. The transformer-used rare earth boron copper alloy transposed conductor comprises an odd number of enameled copper flat wires and the odd number is more than 3; after all enameled copper flat wires are transposed, the enameled copper flat wires are wrapped with an outer insulated layer; each enameled copper flat wire comprises a rare earth boron copper alloy flat wire and a film layer coating the outer surface of the rare earth boron copper alloy flat wire; and the rare earth boron copper alloy flat wire is composed of, by weight, 0.012 to 0.027 parts of lanthanum, 0.004 to 0.010 parts of cerium, 0.0026 to 0.0057 parts of praseodymium, 0.016 to 0.036 parts of neodymium, 0.05 to 0.10 parts of boron and 99.82 to 99.91 parts of copper. The conductor of the invention has good electrical conductivity, thermal conductivity and mechanical performance, the wear resistance is improved, the mechanical strength is high, and the anti-short circuit impact performance is improved.