Drainage structure capable of greatly reducing drainage amount of long-distance steam pipeline and working method of drainage structure

The invention discloses a drainage structure capable of greatly reducing the drainage amount of a long-distance steam conveying pipeline and a working method of the drainage structure, and solves the problem of how to reduce the drainage amount of the long-distance steam conveying system. An outer casing pipe valve sleeve (3) is arranged between a left side steam conveying pipeline (1) and a right side steam conveying pipeline (2), a drain water discharging outer through hole (4) is formed in the side wall of the bottom end of the outer casing pipe valve sleeve (3), an arc-shaped long-strip-shaped hole (5) is formed in the side wall of the upper portion of the outer casing pipe valve sleeve (3), the arc-shaped long-strip-shaped hole (5) is formed along the outer circle of the outer casing pipe valve sleeve, an inner casing pipe valve element (6) is movably sleeved with the outer casing pipe valve sleeve (3), a drain water discharging inner through hole (8) is formed in the side wall of the bottom end of the i