Herein, numerical simulations for single‐jet impingement cooling of a heated seamless steel tube are carried out. The effect of water flow, jet height, and jet position are analyzed during numerical simulations. Water flow varies from 2 to 10 L min−1, jet height varies from 10 to 50 cm, and jet position gradually rotates from right above steel tube (α = 90°) to bottom (α = −90°). The distribution of pressure, turbulence kinetic energy, Nusselt number, and surface temperature of steel tube are obtained. This analysis reveals that water flow is an important factor affecting heat transfer efficiency. With the increase in water flow, the improvement of heat transfer efficiency gradually decreases. The cooling capacity of the steel tube in the circumferential direction is greater than that in the axial direction of the steel tube. In contrast, as the jet height gradually increases at α = 90°, the Nusselt number increases first and then decreases. In addition, the jet position also seriously affects the cooling capacity of the jet. When the jet is stationed at the top and bottom, the cooling capacity deviation between the two reaches the maximum.