The invention discloses a supersonic radial-inward-flow turbine which is used for solving the technical problems that a traditional single-stage radial-inward-flow turbine cannot meet the condition that the requirement for inlet pressure is higher and higher and the expansion ratio required by a system is continuously increased. The embodiment comprises Lafar spraying pipes, a centripetal impellerand a circular ring shell surrounding the centripetal impeller; and a plurality of air inlets are evenly distributed on the outer side wall of the circular ring shell, the Lafar spraying pipes are arranged inside the circular ring shell, the inlet ends of the Lafar spraying pipes communicate with the inlet inlets, and the outlet ends of the Lafar spraying pipes face the center of the centripetalimpeller. In the embodiment, the Lafar spraying pipes are arranged between the inlet inlets and corresponding inlet outlets, the pressure of the high pressure air can be converted into high-speed kinetic energy through the Lafar scaling spraying pipes, the Mach number of outlets of the spraying pipes can usually reach 2 or more, the radial entry high-speed airflow can push the centripetal impellerto rotate to the rated speed, the air continuously expands in the centripetal impeller, and the using requirement is met.