The invention discloses a commercial water drinking machine. The commercial water drinking machine comprises a casing and a heating element fixed in the casing, wherein the heating element comprises a metal heating tube, and an insulating tube sleeving the exterior of the metal heating tube, with the outer surface being wound with a spiral coil; a hot water channel is formed between the insulating tube and the metal heating tube; the heating element is axially and vertically arranged in the casing; a water outlet is formed in the upper end part of the heating element; the water outlet is shunted through a three-way connector; a boiled water outlet tube and a warm water outlet tube are connected with the three-way connector; a water inlet is formed in the lower end part of the heating element; a preheating pipeline is connected with the water inlet; the preheating pipeline comprises a primary preheating pipe section performing heat exchange with a power device of the commercial water drinking machine and a secondary preheating pipe section performing heat exchange with the warm water outlet tube. The commercial water drinking machine is safe to use, low in energy consumption, high in heating rate and convenient to take water.