The invention discloses an efficiency improving and cost reducing method for pipe end expansion and a special expansion mold. Through the mated expansion mold, the method can change pipe end expandersof axially pressing the expansion mold into the pipe ends of clamped steel pipes through pressure for expansion as pipe end expanders for pipe end expansion through radial extension by multiple fan-shaped modules under the effects of inclined surfaces; and due to change of the expansion mode, the specification, the number and the replacement times of the expansion mold can be reduced, and three procedures of clamping, coating and lubricating agent cleaning in pipe end expansion of the steel pipes are saved, so that the production efficiency and the cost in pipe end expansion are greatly improved. In the mated mold, the mold with one specification can be suitable for pipe end expansion of the steel pipes in a certain inner diameter range without needing clamping of the steel pipes and lubrication of a working surface of the mold.