The utility model discloses an automatic temperature control biogas experimental device which prepares biogas by carrying out dry fermentation with crop straws and animal waste as raw materials in a lab; the device comprises a fermentation device, a heat increasing and insulating device and a measurement device, wherein the fermentation device comprises a tank body and an exhaust valve, and the exhaust valve is arranged on the top of the tank body; the heat increasing and insulating device comprises a heater and heat insulating material, the heater is wound on the side wall of the tank body, the heat insulating material is arranged on the periphery of the tank body and the heater, and the side wall of the tank body is a two layered structure which comprising the inner wall and the outer wall of the tank body; and the heat increasing and insulating device is further provided with a temperature controller, a temperature sensor and water, the temperature controller and the water are arranged between the inner wall and the outer wall of the tank body, the temperature sensor transmits water temperature information to the temperature controller, and the temperature controller adjusts the water temperature by controlling the heater. The device can keep the experimental temperature at a set value, thereby improving the experimental accuracy and safety.