Tensile test experiments with flat specimens for SPCC and JAC340H are presented and simulated in this paper. Digital image correlation (DIC) technology is used to measure the deformation during tension procedure, and the accuracy of the home-developed DIC equipment is discussed. The 3-D finite element models of tensile specimens are developed to analyze the influences of different yield functions upon evaluating the engineering stress-engineering strain relationship, load-true strain curve, transversal-longitudinal true strain relationship and the distribution of longitudinal strain after necking. The comparisons between the simulations and the experimental results show that the Barlat 1991 yield function offers better results than the von Mises yield function and Hill 1948 yield function do.