Abstract: Continuous casting is the key link of iron and steel production, and the cooling effect of its secondary cooling zone(secondary cooling zone)directly affects the quality of slab. The cooling heat flux density in the secondary cooling zone is an important basic data for the rational design of secondary cooling water distribution. Aiming at the high temperature and high heat flux conditions involved in continuous casting secondary cooling, a set of heat transfer experimental device for continuous casting secondary cooling jet cooling slab was developed based on the steady-state heat flux measurement method, which can be used to measure the heat flux density of high temperature surface jet cooling at 900-1 200 ℃. During the experiment, the surface of the local area of the high temperature steel material was cooled by the mist jet. The cooling object was a specimen with a diameter of 10 mm and a thickness of 2.5 mm, and the induction heating was used as the internal heat source to keep it in a high temperature state. The PID controller adjusts the output power of the high-frequency generator to balance the heat taken away by the induction heating and jet cooling of the cooling object, so that the specimen is maintained at the set temperature. The electrical parameters of the output power of the induction heater are measured when the temperature of the cooling object is maintained, and the heat flux density of the surface heat dissipation of the jet cooling specimen is calculated by the induction heating mathematical model. The experimental results show that the equipment can realize the measurement of the cooling heat flux density of the high temperature surface by the typical continuous casting secondary cooling air mist jet on the surface of the high temperature slab,and the distribution of cooling heat flux density in the jet area shows the trend of high center and low edge.When the nozzle is used to cool the specimen with a surface temperature of 1 200 ℃ under the conditions of air pressure of 0.3 MPa and water pressure of 0.8 MPa, the heat flux density can reach 4.78 MW/m² The heat flux of jet cooling does not increase significantly with the increase of cooling surface temperature.