Hydraulic methane septic tank

The utility model discloses a hydraulic methane septic tank, which comprises three stage septic tanks, and the three stage septic tanks are connected through through-holes (6), wherein a cushioning well (1) is arranged before the first-stage septic tank (9), and discharge pipes (2) which are communicated to the externals of the tanks are installed in the first-stage septic tank (9) and the second-stage septic tank (8), the tops of the tanks are provided with sealed pyramid air storing chambers (3), and are provided with gas transmission pipelines (4), and a drain outlet (5) of the third-stageseptic tank (5) is connected with a city sewage pipe network. The methane septic tank has simple structure and less investment cost, after adopting design of the hydraulic type septic tank, not onlymethane and highly-effective and good-quality organic manure can be obtained, but also various harmful germs and parasitic ovum can be killed, and hygienic and clear environment is kept.