A random phase modulation method depending on a communication distance is provided. In the method, time synchronization is carried out by means of a transmitter and a receiver, a local random signal is generated, and an original signal to be sent is pre-coded according to a transmission delay and the generated local random signal, such that random phase modulation depending on a communication distance is realized, potential security brought about by positions of the transmitter and the receiver is fully utilized, a receiver at an expected distance position can receive a signal with a correct phase, and a receiver at another distance position receives a signal with a scrambled phase, thereby improving the secure communication capability of a wireless communication system in terms of the dimension of space.