The utility model relates to a pipeline valve for a negative pressure pipeline. The utility model relates to the technical field of vacuum dust collection of lead-zinc smelting auxiliary equipment. The left end and the right end of the fixed valve seat are connected with an inner threaded connection pipe and an outer threaded connection pipe correspondingly. a mounting sleeve head is arranged at the top of the fixed valve seat; the valve core is inserted downwards along the top of the mounting sleeve head; the top of the valve element is sleeved with a limiting cover plate. a spring mounted atthe top of the valve core is arranged in a gap between the limiting cover plate and the valve core; a rotating handle is mounted at the top of the limiting cover plate; the handle is inserted into the top of the valve core along the limiting cover plate; the automatic reset sealing device is flexible in assembly, good in air tightness, convenient to use, simple, convenient and reliable in connection, and capable of achieving automatic reset sealing, meanwhile, the vacuum degree of the position of a fixed connector of the automatic reset sealing device can be reduced, a cover plate of the fixed connector is easy to open, materials can resist corrosion and friction, and the service life of the whole device is prolonged.