The invention discloses a high-precision polymer sealing ring for a turbine rotor, and relates to the field of turbine rotors. The sealing ring comprises a first alloy seal ring, a rubber seal ring and a second alloy seal ring, wherein a first gasket is fixedly adhered to the right side of the first alloy seal ring, a second gasket is fixedly arranged on the left side of the first alloy seal ring,a first opening gap is formed in the first alloy seal ring, first foam is fixedly bonded to the middle between the first gasket and the rubber seal ring, second foam is fixedly bonded to the right side of the rubber seal ring, and a third gasket is fixedly adhered to the middle between the second foam and the second alloy seal ring. According to the sealing ring, a Z-shaped opening gap is formedin one side end of the first alloy seal ring, so that the sealing effect of the turbine rotor is further improved, the oil leakage rate is reduced, the three seal rings are bonded together, a spring is mounted inside the rubber seal ring, and the compressive capacity is enhanced.