Abstract: The approach to UQPSK carrier synchronization is widely used in digital satellite communication and UAV transmission of ground and tracking system. But it is hard to realize the related recovery modes for only analog signals or complex loop. So a modified approach to UQPSK carrier synchronization was presented based on decision feedback phase locked loop (PLL) with the constellation characteristics of UQPSK signal. The approach was arranged to be implemented quickly for phase compensation and fast phase capture with fast convergence speed under the condition of low signal-to-noise ratio. The simulation and analysis results of UQPSK carrier synchronization system show that the BER of the approach to UQPSK carrier synchronization is similar to the theoretical BER, and there is the high reliability in system.