Plastic manhole usually called "inspection well" which is placed at interchange and turning point at drainage pipe, changes and plunge of caliber or slope, and in straight pipe at each certain distance. It is affiliated drainage structure used to check, clean and dredge the pipe regularly. Our plastic manhole is made of polymer resin, adopts combinative structure, and consists of manhole base, manhole cover, manhole shaft, cover base and concrete supported plate etc. The critical manhole base adapts one-time molding, which can produce all types of plastic manhole for two-way, three-way, Cross Tee 90-165 degree any interchange. It uses reduce union, variable angle union, and seal ring to change the connection of caliber and angle. Our manhole shaft uses PE pipe, corrugated pipe or winding pipe to adjusted itself, so it is very flexible, we can intercept the corresponding length according to the site buried length. We use rubber seal ring at the connection of manhole shaft, inlet(outlet) pipe and manhole base, so that small inner angle changes can be made. It is convenient to install, not easy to leak, enviroment friendly and energy saving.