As the data volume of communication system increases, the peak ratio of communication system increases continually.Power amplifier is one of the most power-consumption devices in the terminal. Envelope Tracking can dynamically adjust the supply voltage in real time according to the envelope of input signal of power amplifier, improving the efficiency of power amplifier.Compared with other technologies, Envelope Tracking technology has high linearity, high efficiency, wide dynamic range. It is easy for implementation, and is suitable for systems with high PAPR. Therefore, it has broad prospect in application.