The invention provides a digital automatic gain control method based on echo amplitude statistics. Through an energy value of a receiving signal, an energy band is divided. According to a statistics method, frequencies of the signal falling into different energy scopes are calculated so that a signal energy interval is determined and the receiving signal is enlarged or reduced. Therefore, a purpose of controlling a gain smoothly and accurately is reached. The method based on statistics processing is applied to an automatic gain control process and an absolute gain is acquired. A relative gain which carries out a little change on an original signal is obtained. A signal amplitude can be smoothly and accurately adjusted to an ideal scope. By using the method in the invention, automatic adjustment to an echo receiver gain can be realized and an influence of signal fluctuation on receiving of the receiver is prevented; the design adopts a full digital method and the method is suitable for a circuit in which various systems of radars carry out accurate control on an intermediate frequency receiving signal gain.