In view of the problem that the traditional static parameter equivalent circuit model of the supercapacitor cannot effectively reflect its dynamic operating characteristics, a second-order ladder equivalent circuit model including dynamic charge/discharge resistance and capacitance parameters is proposed. The recursive least square method is used for the offline parameter identification of the second-order ladder equivalent circuit model at first. Furthermore, by considering the dynamic change of the supercapacitor parameters, the offline identified model parameters are used as initial values. Then, the recursive least square method with forgetting factor is introduced to identify the dynamic parameters of supercapacitor in real-time. Simulation model and experimental test platform of the supercapacitor are established. On this basis, the effectiveness and accuracy of the second-order ladder equivalent circuit model with dynamic parameters and the real-time identification method are verified through the comparison of simulation and experimental results. Results show that the second-order ladder equivalent circuit model with dynamic parameters can effectively reflect the dynamic charge/discharge operating characteristics of the supercapacitor. Compared with the traditional three branch and second-order ladder equivalent circuit models with static parameters, the model accuracy is improved over 2.08% and 3.56%, respectively.