The invention discloses an auction theory-based power distribution method in relay communication, and relates to the technical field of wireless communication. The method mainly solves the problem of power distribution under the conditions of complete information and incomplete information and sets the target bit error rate for ensuring that a destination node receives effective information. Under the complete information condition, a relay node calculates the auctioned optimal scale value according to a scale value price and all channel information by using an auction theory to acquire maximum gain; and under the incomplete information condition, the relay node regulates the scale value by adopting an update iteration algorithm, and applies a power server for power to acquire maximum gain. The method also sets the target bit error rate to ensure that the destination node receives the effective information.