The present disclosure provides a ratooning rice harvesting header and a harvester including the same. The ratooning rice harvesting header includes a multi-layer adjustable disc cutter, a header, and an ear cutter. The multi-layer adjustable disc cutter is mounted below the header and located below a rear portion of the ear cutter. The ear cutter is mounted at a front end of the header. The multi-layer adjustable disc cutter includes at least one group of multi-layer disc cutting assemblies. Each group of multi-layer disc cutting assemblies includes two multi-layer disc cutting assemblies. Each of the multi-layer disc cutting assemblies includes three layers of vertically arranged blades. The use of the multi-layer adjustable disc cutter in cooperation with the ear cutter can reduce the straw-grain ratio of the part cut from the crops to reduce the power consumption of the harvester.