A novel water-cooling cavity structure of a vertical pit-type furnace with a furnace pot belongs to the field of equipment for heating processing. High-temperature resistance fibers are filled between an upper opening of the furnace pot of the vertical pit-type furnace and a water-cooling cavity. The novel water-cooling cavity structure is characterized in that a furnace lid 1of the vertical pit-type furnace is arranged on the furnace pot 2 and sealed through a sealing strip 5, and the high-temperature resistance fibers 3 are filled between the high-temperature furnace pot 2 and the water-cooling cavity 4. The water-cooling cavity is no longer in direct contact with a high-temperature muffle, thereby isolating direct heat exchange between the water-cooling cavity and the high-temperature muffle, reducing temperature difference of the upper opening of the furnace pot, decreasing alternating stress generated at the upper opening of the furnace pot due to temperature change, and prolonging service life of the furnace pot. Simultaneously, furnace-inside heat which is taken away by cooling water is reduced, thereby reducing energy consumption of equipment.