As one of the means of light-weight, more and more ultra-high strength steel has been applied to car body. The plasticity, damage and fracture behavior of UHSS under complex stress state is the key to accurate simulation of forming process and crash. The newly developed high elongation QP steel and press-hardening steel of Baosteel were tested under different loading conditions, including shear, uniaxial tension, plane strain tension and biaxial tension. With the help of digital image correlation technology, the development of plastic strain under various stress states was analyzed. Based on the testing results and numerical simulation, the parameters of plasticity and fracture model of UHSS were obtained. The validity of the model was verified by comparing the stamping and crash test results of component made by QP and PHS steel. The research results will provide guidance for parts design and structural design in the application of UHSS.