The utility model discloses a thermos with a temperature controller fixing mechanism, which comprises a thermos body, a first extension block is embedded and fixedly arranged on one side of the thermos body, a clamping groove is formed in the center of the first extension block, a temperature controller is arranged in the clamping groove in a sliding manner, an extension groove is formed in the first extension block, and the temperature controller is arranged in the extension groove in a sliding manner. A second extending block is fixedly arranged on the outer side of the temperature controller, and a display screen is fixedly arranged on one side of the temperature controller in an embedded mode. During use, a circuit is connected and then plugged into the clamping groove, then the temperature controller is fed into the clamping groove, the extension block is clamped in the extension groove at the moment, then the limiting block is rotated, the limiting block extrudes the sliding block, the sliding block moves along the interior of the groove body and drives the limiting rod to move, the limiting rod penetrates into the limiting groove, and the temperature controller is placed in the clamping groove. And meanwhile, the spring is extruded and compressed until the outer side of the limiting block is tightly attached to the outer side of the sliding block, so that the temperature controller is fixed in the clamping groove, and the installation work of the temperature controller is facilitated.