The utility model provides an adjustable nozzle ring mechanism of the marine radial-flow exhaust gas turbo supercharger, comprising a nozzle vane (2) and a nozzle ring (2'). The utility model is characterized in that a plurality of the nozzle vanes (2) and the nozzle rings (2') are separately equipped; the shaft (110) of the nozzle vane (2) can rotationally thread a hole (110') of the nozzle ring (2'); one end of the shaft is connected with a gear (11); a plurality of the gears (11) is meshed with a geared ring (10); and the utility model also includes elements which make the geared ring (10) to revolve. Changing the orientation of the nozzle vane through the mechanism can provide the aperture of larynx area with different areas, thereby realizing that the diesel engine can enhance the operating rotary speed of the supercharger and the pressure of the compressed air in different efficiencies, satisfying the requirement that the diesel engine always keeps low emission and high efficiency when in the capability of starting and low-load operating.