For three different strength level， different thicknesses were systematically formability test，Comprehensive analysis of the mechanical properties of （dual- phase）DP steel，cupping performance，cold bending，forming limit. Studies show that：Elongation and the value of n for DP steel decreases with rising intensity level. Cupping test results show that the height of the cupping with the DP steels up strength level decreases，and increases with increasing thickness of the material. Duplex steel cold bending properties with increased material strength level decreases. Bulging under biaxial strain tests showed that DP steel has good formability. Based on mild steel FLD0 empirical formula can’t be directly applied to the DP steel.