The invention discloses a methane tank, comprising a bottom tank, an impermeable layer, a feeding tank, a slag discharging tank, a tank body, a top cover, an air vent and a water filling port, wherein the bottom tank is provided with the impermeable layer, the feeding tank is arranged at one side of the bottom tank, the slag discharging tank is arranged at the other side of the bottom tank, the tank body is arranged above the bottom tank, the top cover is installed above the tank body, the center of the top cover is provided with the air vent, and the water filling port is arranged on the top cover. Thus, the methane tank provided by the invention has the advantages of convenience in usage, seepage prevention, no pollution, a simple structure, low cost, a great gas production amount and wide market prospects in the field of methane tanks.