Abstract: The effects of reduction, coiling temperature and finish rolling temperature on the refinement of microstructure and mechanical properties of hot-rolled dual-phase steel were investigated in laboratory. It was found that the deformation process parameters affect greatly the microstructure and mechanical properties and there are three typical microstructural morphologies, which cause the hot-rolled dual-phase steel in different toughening mechanism and mechanical properties. The tensile strength of the steel developed in the laboratory by controlling the process parameters with Mn and Si as main alloying elements comes up to the Grade 780 MPa with high percentage elongation.