Abstract: For developing new kind of DP steel, Q345 steel was cold-rolled and then the continuous annealing process was simulated. Microstructural and mechanical results showed that the microstructure is complicated and the matrix is composed of ferrite, pearlite and martensite. The samples exhibit the high tensile strength and the low yield ratio. The elongation percentage is very low, only about 14%. Because of high carbon content, the conventional heat treatment process couldn't be adopted and only low soaking temperature and the higher starting temperature of rapid cooling should be adopted.