The invention relates to a boiler header of an ultrahigh steam parameter unit of more than 650 DEG C. The boiler header comprises a header body and a tube base. One end of the tube base is welded with the header body, and the other end is welded with the pipe of a superheater or a reheater. The boiler header is characterized in that the header body is manufactured by a nickel base alloy large-diameter tube, and the tube base is manufactured by a nickel base alloy small-diameter tube. The material of the boiler superheater outlet header or the reheater outlet header applied in a steam parameter unit of more than 650 DEG C is nickel base alloy large-diameter tube. The tube base made of the nickel base alloy can be applied in operating temperature of higher than 650 DEG C, high-temperature oxidation performance of the material is excellent, and the boiler header has excellent practical value. The nickel base alloy and the superheater or the reheater are welded by an austenite steel small-diameter tube, and postweld heat treatment is not needed, so processing steps are reduced, and production is accelerated.