NOVELTY - Marsh gas tank discharging control system comprises a gas output detector, a controller and a discharging pump. The gas output detector is used for detecting the output of the marsh gas in marsh gas tank. The controller is connected with the detector, which is used for comparing the detected gas output with the preset threshold value, and when the detected gas is less than or equal to the preset threshold value, generating the discharge signal and sending it to the discharge pump. The discharging pump is set at the bottom of the marsh gas tank.    USE - Used as a marsh gas tank discharging control system.    ADVANTAGE - The system can perform quantitative analysis to control output of the marsh gas tank so that it can more accurately produce marsh gas for carrying out judgment, and when the gas generating ability is insufficient, it can discharge the marsh gas in the marsh gas tank; can easily change the marsh gas slurry in the marsh gas tank; can sustain balanced supply of marsh gas; and is convenient for the user to use the marsh gas.    DETAILED DESCRIPTION - Marsh gas tank discharging control system comprises a gas output detector, a controller and a discharging pump. The gas output detector is used for detecting the output of the marsh gas in marsh gas tank. The controller is connected with the detector, which is used for comparing the detected gas output with the preset threshold value, and when the detected gas is less than or equal to the preset threshold value, generating the discharge signal and sending it to the discharge pump. The discharging pump is set at the bottom of the marsh gas tank. The biogas liquid in the marsh gas tank is pumped out of the marsh gas tank according to the discharge signal. An INDEPENDENT CLAIM is also included for kind of marsh gas tank discharging control method, where the marsh gas tank is provided with a discharge pump, comprising detecting gas content of marsh gas tank, comparing detected gas content with preset threshold value, judging whether gas output rate is less than or equal to the preset threshold value, when the gas content is less than equal to the preset threshold value, and controlling the marsh gas slurry discharge via the discharging pump in the marsh gas tank.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the marsh gas tank discharging control system (Drawing includes non-English language text).