In this study, a new method of building a dynamic load model for dynamic stability analysis was proposed. This method is as follows: First, inject some small electric power disturbance of known pattern to power system and measure the response in distribution system. Next, analyze the measured response using system identification and create the load model. Simulation was performed with PSCAD, and a dynamic load model was build and evaluated. In the simulation, the availability of the proposed method was confirmed. The model could reproduce the response of the stable system precisely. In addition to it, the stability of the system could evaluate with proposed method.