The invention discloses a temperature detection device. The device comprises a protection casing pipe, thermocouples arranged in the protection casing pipe and thermal conduction rings. The plurality of thermal conduction rings are arranged at detection point sites with intervals along an axial direction in the protection casing pipe and are contacted with an inner wall of the protection casing pipe. A temperature measurement end portion of each thermocouple is fixed to an upper portion of the corresponding thermal conduction ring and the two are located in a same horizontal plane. The temperature detection device can detect an activated carbon temperature on the same horizontal plane and can rapidly measure a temperature in an adsorption tower. The temperature is close to the actual activated carbon temperature. Reliability, accuracy and real-time performance of temperature detection are guaranteed and problems that an existing temperature detection device is lag; a response is slow; an error is large and so on are avoided. The invention also discloses an activated carbon desulfurization system provided with the temperature detection device.