The true stress-strain relationship and ductile fracture characteristics of Chinese Q690 high strength structural steel were investigated at different low strain rates. Sheet Q690 specimens with one unnotched and two different notch geometries were used for uniaxial tensile tests, and pure shear sheet specimens were also used for shear tests. These specimens were loaded to obtain a wide range of stress states. A hybrid experiment-simulation approach was used to determine the equivalent plastic strain to fracture, the stress triaxiality and the Lode parameter. The results showed that the stress triaxiality and the Lode parameter are the key factors controlling fracture, and that the strain is more sensitive to strain rate as compared to stress. It was observed that the equivalent plastic fracture strain increases with increasing strain rate. Further studies are required to design pure shear specimens since it is difficult to realize pure shear stress state on the fracture sections in most of the pure shear tests due to the obvious deformation and stress concentration before a fracture occurs at the gauge area.