Abstract: To actualize carrier synchronization under low signal-to-noise ratio(SNR) and high dynamic condition,a carrier tracking method combining FLL(frequency-locked loop) with PLL(phase-locked loop) is presented.An improvement on cross-product automatic frequency control(CPAFC) loop,which be commonly used,is preformed.The improved frequency discrimination algorithm has higher capture speed than CPAFC loop.The whole loops are simulated by MATLAB and the results show that the question of fast carrier acquisition and accurate tracking is solved effectually by these loops.