The utility model provides a temperature control box used for an on-line chromatographic analyzer. The temperature control box comprises an inner container, a chromatographic column, a thermal insulation material, a metal reinforcing part, a heat source and a temperature sensing component, wherein the chromatographic column is inlaid in the outer surface of the inner container, the outer diameter of the inner container is equal to the inner diameter of the chromatographic column, the thermal insulation material is wrapped on the outer surface of the chromatographic column, the metal reinforcing part serves as a shell made from a metal material at the periphery of the thermal insulation material and can be used for reinforcing the internal thermal insulation material and the inner container, the distance between the heat source and the temperature sensing component is 5mm, and both the heat source and the temperature sensing component are arranged in the inner container and respectively connected with a control circuit board outside the temperature control box through connecting lines. The temperature control box is small in volume, low in energy consumption and noise, high in temperature control precision and wide in applicable environment.