The utility model discloses a two-way sealing piston ring, which comprises an up-and-down lap joint structure and a left-and-right lap joint structure, which are arranged at the opening of the ring end; the length of the up-and-down lap joint face is less than that of the left-and-right lap joint face; the up-and-down lap joint structure is arranged outside the left-and-right lap joint structure and comprises a ring outer edge line, wherein, the left-and-right lap joint structure occupies the two fifths of the width of the range between the ring inner edge line and the ring outer edge line. The utility model has the advantages of stably blocking the axial and radial gas leakage channel at the fracture of the piston ring, effectively reducing the gas leakage of the piston ring opening, increasing the power, saving oil, sufficient burning, reducing the carbon laydown and environment protection.