Oil seal for preventing gas leakage

The utility model discloses an oil seal for preventing gas leakage, comprising a U-shaped groove circle body. The inner wall of the U-shaped groove circle body comprises an annular bulge-shaped lip opening; a cylindrical framework is affixed at the bottom end of the U-shaped groove circle body; and the outer wall of the U-shaped groove circle body comprises two annular lip openings. The oil seal can ensure the verticality of the sealed cylinder and a strut bar reciprocates without shifting the product; the outer lip opening and the cylinder wall are in interference fit with each other; and the sealing surface has favorable sealing performance.