Abstract: The mechamical properties and microstructure evolution of QP980 steel was studied though static and dynamic tensile tests with the strain rates ranging from 10^-3-500 s^-1. Scanning electron microscopy（SEM） and electron back scatter diffraction（EBSD） were used to observe the fracture morphology and microstructure evolution near the fracture. The results show that coarse block retained austenite is first transformed into martensite, and only ultrafine retained austenite grains are left in the microstructure. The retained austenite at the corner of three boundaries is more sensitive to strain rate. The volume fraction of retained austenite decreases sharply with the increase of strain rate. The uniform elongation of QP980 steel increases significantly due to the accelerated transformed TRIP effect and BCP effect. As the strain rate increases, the dimples have become smaller and deeper. When the strain rate increases to 500 s^-1, some regions are composed of slender and uneven dimples. These long strip-like dimples are large initial void defects generated by the fragmentation of massive martensite laths.