The temperature distribution curves at core

1/2 radius and surface of the Φ35 mm round bar of 20CrMnTiH steel have been got by finite element simulating and situ temperature measuring to finishing rolled round steel bar during controlled cooling. Analysis results indicated that the temperature at surface of finished rolled round bar quickly dropped during water cooling while the temperature at core of steel decreased slowly ； the maximum temperature difference between the surface and the core of round bar was about 115 ℃ during water cooling ； and after water cooling the temperature of surface and core of round steel tended towards equality during air cooling. To adopt quick water cooling and combined air cooling process is available to inhibit austenite grain growth and obtain fine and dispersed structure of finished rolled 20CrMnTiH round steel products.