The invention discloses a high-temperature-resistant high-pressure Y-shaped ring combined sealing structure. The sealing structure comprises a sealing body, a Y-shaped sealing ring, a sealing ring ofa triangular cross section and two metal sealing rings of a trapezoidal cross section, wherein a rectangular groove is formed in the cross section of the sealing body, the groove extends in the direction of the sealing body, a slope is arranged at the right lower part of the cross section of the Y-shaped sealing ring, the slope is in contact with the sealing structure of the sealing ring of the right-angle triangular cross section, the two right-angled trapezoid slopes are in contact with each other, and the surface of the higher trapezoidal sealing ring is in contact with the surface of the right-angled edge of the cross-section right-angled triangle. The sealing structure effectively solves the leakage problem in the operation process of the sealing structure, and can achieve a good sealing effect under severe conditions.