This utility model relates to a heating device of connecting tube between horizontal continuous casting pouring box and crystallizer, which is consisted of fire-resisting material tube, heat-proof tube, electric heating element, transformer and control power supply. The fire-resisting material tube is covered on the connecting tube, the wire-shaped electric heating element twists on the external surface of fire-resisting material tube, the electric heating element adopts small pitch dense layout near the crystallizer end, adopts big pitch loose layout near the pouring box end, and the surrounding area of electric heating element is sealed via heat-proof tube. This utility model can easily control pouring temperature, keep the liquid-solid interface in the inside lining of crystallizer, guaranties favorable metal horizontal continuous casting; moreover, implement constant low-temperature pouring with low energy consumption, extend the service life of fire-resisting material of furnace lining, and enhance the casting blank quality.