The left and right door blades rotate around the vertical gate axis in the side wall of the channel, and when the channel is closed, the gate shaped like a "man" is overlooked. When the miter gate works, the two leaves form three hinged arches to bear the water pressure; When the channel is open, the two door leaves are located in the door niche on the side wall, and are not under water pressure and are not in working condition. Miter gate generally can only withstand one-way water pressure, but can only be operated in the upper and lower water levels are equal, static water conditions, the most used for navigable river lock, as a working gate arranged in the upper and lower head.