Piston type single-channel drainage

According to the present invention, mechanical pulling force and pushing force are utilized to make a piston move so as to provide effects of drainage channel hole opening and drainage channel hole clogging closing; and a special-shaped and multi-limb single-channel drainage port is arranged at the drainage port position, such that the drainage port and the drainage channel are the single channels, hair and other liner substances can not be hooked, and only the S-shaped drainage pipe is used to connect the drainage connection port of the drainage without drainage cleaning.