Abstract: Uneven temperature distribution in cooling process are produced inevitably, causing the uneven distortion phenomenon in H-beam cross section. This research focused on how to improve H-beam cooling distortion. The cooling distortion was simulated in the ultra-fast cooling process by finite element analysis software ANSYS. The simulation results are in good agreement with the measured data. The cause of out of square is large residual stress due to the uneven cooling rate between upper and lower groove of the H-beam. Both simulation results and measured data showed that the out of square can be solved by improving the structure of ultra-fast cooling equipment layout and process control mode.