Abstract: To study the difference of cooling intensity obtained between the two technical methods for cooling the hot rolled strips of laminar cooling (intensive cooling) and using pressurized jet of cooling water for ultral fast cooling(UFC)， a numerical calculation method was used to get heat transfer coefficients between the surface of hot strips and the cooling water under different cooling methods and mass fluxes. By comparison of the results some conclusions were obtained: the cooling capacity of the ultrafast cooling is greater than that of the intensive cooling method with the same mass flux. The heat transfer coefficient of the surface of hot strips increases with the increase of the mass flux and after reached to an certain value， it decreases with the increase of the mass flux when using the intensive cooling method. However the heat transfer coefficient doesn’t decrease obviously when using the ultrafast cooling method.

Key words: ultrafast cooling(UFC), intensive cooling, cooling intensity, mass flux, heat transfer coefficients