Regenerative reheating furnaces for the rolling process are widely used in steel plants because of its energysaving and emissionreducing characteristics. However, negative effects including high furnace hearth pressure and high electricity consumption in fans occur due to its forced flue gas extraction and air supply modes. The regenerator is a key component of the regenerative reheating furnace, and it is important to understand the pressure distribution in the regenerator of the furnace. Differing from the previous cold state experiment and numerical simulation, a semiindustrial experimental setup was established to conduct the hot state experiment, with furnace No.1 of Ansteel continuous rolling sector as the prototype. It was concluded that, under the flue gas extraction condition, the pressure inside regenerator will increase with the increase of flue gas velocity. While, under the air supply condition, the pressure inside regenerator will increase with the increase of furnace hearth temperature. For a given length of a regenerator, the pressure loss of the flue gas extraction process was higher than that of the air supply process. Pressure losses of both flue gas extraction and air supply processes will increase with the increment in the length of the regenerator.