The invention relates to a low-pressure turbine rotor structure design of an aero-engine and a gas turbine, in particular to a high-rotation-speed low-pressure turbine rotor structure. The high-rotation-speed low-pressure turbine rotor structure comprises a torque transmission shaft, a first disk assembly, a second disk assembly, a third disk assembly, a first sealing ring, a second sealing ring, a torque transmission disk, a front balance block, a rear balance block and an axial limiting piece, wherein the first disk assembly, the second disk assembly and the third disk assembly are arranged successively; the first sealing ring is fixedly arranged between a first backward extension arm and a second forward extension arm, and the second sealing ring is fixedly arranged between a second backward extension arm and a third forward extension arm; the inner mounting edge of the torque transmission disk is fixedly connected with the torque transmission shaft, and the outer mounting edge of the torque transmission disk is fixed between the second sealing ring and the third forward extension arm of the third disk assembly; the axial limiting piece is used for axially limiting blades in the disk assemblies. The high-rotation-speed low-pressure turbine rotor structure is a high-rotation-speed three-stage low-pressure turbine rotor, the torque is output from the torque transmission disk to be arranged between the second disk assembly and the third disk assembly, the reasonable and reliable layout of the disk assemblies at high rotation speed is ensured. The structure is stable, and the stable running at high rotation speed can be met.