The research method of identification of the electronic equipment's power-on characteristics based on the data of bus voltage ripple is introduced. The main purpose is to achieve the recognition of the equipment's power-on characteristics through a certain algorithm design, and provide reference for the follow-up intelligent applications of the bus-ripple-tester. Two methods are used here. One is frequency spectrum analysis based on the collected signals. Due to the differences of spectrum distribution between these equipment's signals collected before and after their power-on time, the frequency band of each equipment's characteristic distribution is different, which make it possible to achieve the purpose of identification. The other is the time-frequency analysis based on wavelet transform. According to the difference of wavelet energy of the equipment's signals collected before and after their power-on time, the equipment can be recognized.