In order to reveal more information and understand the behavior and failure mechanisms of high strength steel endplate connections, a full-scale experimental and numerical study is carried out and presented in this paper. Moreover, their experimental behaviors are compared to the numerical results and relative provisions of Eurocode 3. The test results show that the failure mode of high strength steel end plate connections is bolt failure with flange yielding, and the rotation capacity of high strength steel beam-to-column end plate connections is sufficient. Furthermore, the component-based method of Eurocode 3 based on mild steel connections is used to calculate the plastic resistance and to predict the failure mode of high strength steel end plate connections, but it is not suitable to predict their stiffness. Meanwhile, the suggestions on rotation capacity of connections proposed in Eurocode 3 are too conservative for high strength steel end plate connections. The validation of this numerical modelling against all representative experimental results is further verified on moment-rotation relationship and failure mode, which shows good agreements.