Temperature adjusting system of anaerobic fermentation tank

The utility model discloses an anaerobic fermentation tank temperature adjusting system which comprises an anaerobic fermentation tank, a thermometer used for detecting the temperature of materials in the anaerobic fermentation tank and a heat exchanger, and a liquid outlet and a liquid return opening are formed in the side wall of the lower portion and the side wall of the upper portion of the anaerobic fermentation tank respectively. A liquid outlet of the anaerobic fermentation tank is connected with an inlet of the heat exchanger through a liquid delivery pipe, a first water pump is arranged on the liquid delivery pipe to convey fluid in the anaerobic fermentation tank into the heat exchanger for heat exchange, an outlet of the heat exchanger is connected with a liquid return opening of the anaerobic fermentation tank through a return pipe, and a second water pump is arranged on the return pipe. And the fluid subjected to heat exchange is conveyed into the anaerobic fermentation tank for heat exchange wit