The present invention discloses a slag-liquid separation type methane tank, which comprises a housing and an inner container. The upper end of the housing is hinged to an end cover. The bottom part of the side surface of the housing is provided with a water outlet. The water outlet is connected with a water pump via a connecting tube. The water pump is electrically connected with a controller. The upper end of the surface of the inner cavity of the housing is provided with a clamping groove. The side surface of the inner container is provided with a clamping block corresponding to the clamping groove. The housing is in movable and clamped connection with the inner container via the clamping block and the clamping groove. The surface of the inner container is uniformly provided with main drain holes and secondary drain holes. The bottom of the inner container is connected with the rotating shaft of a motor. The motor is electrically connected with the controller. The controller is electrically connected with a power supply device. The controller is arranged in the inner cavity of a mounting groove. The mounting groove is arranged on the surface of the end cover. The slag-liquid separation type methane tank is simple in structure. The slag-liquid separation is realized in the high-speed centrifugal manner. Therefore, the separation is faster in speed and better in effect.