Abstract: In order to solve the problems of excessive CSI estimation and feedback overhead caused by the rapid change of channel state information of UAV system and excessive energy loss caused by frequent switching relay, an adaptive relay transmission strategy based on geographic location information is proposed. It predicts the location of the UAV through the variable dimension Kalman filter algorithm, and selects the optimal relay adaptively for cooperative transmission according to the distance between nodes. It ensures the transmission performance of the system while reducing the number of relay switching. The simulation results show that the number of relay switching is reduced by more than 30% compared with that of the random relay strategy and the optimal relay strategy, and the energy loss caused by switching relay is effectively reduced.