Based on the 8-Hex spotweld model, the spotweld failure during coupon test was simulated. A kind of testing equipment was designed for KSII spotweld specimen tension. This equipment was utilized to conduct KSII0° and KSII90° experiments, which can determine the spotweld failure force. The difference between KSII0° test and lapshear test in measuring spotweld tensile shear strength was compared and discussed. Based on the simulation and test results of KSII0°, Young’s modulus and Hardening modulus in spotweld materials properties was determined. The front rail crush test was simulated with the spotweld failure model based on the KSII test. The experiment and simulation results show that the KSII spotweld failure model has an excellent accuracy.