To meet the requirements of automotive collision simulation analysis, the high strain rate dynamic mechanical properties and model of 800 MPa grade high strength dual-phase steel CR440Y/780TDPD+Z commonly used in automotive bodies were studied, and the mechanical properties at eight strain rates ranging from 0.001 s-1 to 1000 s-1 were tested by the hydraulic servo high-speed tensile testing machine, and the extended mechanical property curves were fitted and obtained by the traditional high strain rate constitutive model. Based on the fitting results of five strain strengthening models, a hybrid strain strengthening model was constructed, and based on the extended curves of each strain rate, the strain rate sensitivity index was obtained to construct strain rate strengthening model, which was coupled with the hybrid strain strengthening model to obtain a strain rate-dependent hybrid strengthening model. The results show that the strength and strain rate sensitivity index of materials increase with the increasing of strain rate, while the yield strength ratio remains basically stable at 0.61. The prediction accuracy of the extended curve for the hybrid strain strengthening model on the ultimate cold bending is higher, the deviation of the key parameters is less than 3.5%, and the fitting degree reaches 0.986. For the strain rate-dependent hybrid strengthening model curve, the deviation of key point parameters is less than 5%, and the prediction accuracy of mechanical properties is higher. Comparing the drop hammer crushing test and simulation results of rectangular cross-section beams, the maximum deviation of the key parameters for the strain rate-dependent hybrid strengthening model is 5.22 %, which is better than Johnson-Cook, Cowper-Symonds and other models.