The invention provides a nozzle ring sealing structure which comprises a nozzle ring, a turbine case and a turbine case flange. The inner side of one end of the turbine case makes contact with the outer side of the turbine case flange. One end of the turbine case is fixed to the edge of the turbine case flange, and the other end of the turbine case is provided with a turbine case seam allowance surface and a turbine case groove. One end of the nozzle ring is arranged in the position of the turbine case seam allowance surface, and the outer edge of the nozzle ring is provided with nozzle ring sealing grooves and a nozzle ring positioning boss. The nozzle ring sealing grooves are formed outwards in the circumferential direction of the nozzle ring and are in contact with the turbine case seam allowance surface. The nozzle ring positioning boss is arranged outwards horizontally along the outer sides of the nozzle ring sealing grooves and cooperates with the turbine case groove for circumferential positioning. The turbine case flange is provided with a flange seam allowance surface, a flange sealing groove and flange reinforcing ribs. The flange seam allowance surface makes contact with the inner side of the nozzle ring in the circumferential direction. The flange sealing groove and the flange reinforcing ribs are located on the face, in contact with the turbine case, of the turbine case flange. The nozzle ring sealing structure has the advantages that the structure is simple, and the sealing effect on acting gas is effectively improved.