Abstract: Carrier Identification (CID，Carrier Identification) technology is an innovative technology that has fundamentally solved the problem of radio frequency interference in satellite communication in recent years. In this paper, the despreading and information extraction of the DVB-CID signal are studied, and an anti-frequency offset despreading algorithm based on the carrier cancellation process is proposed,which has low complexity and good anti-noise performance, and can be widely applied to demodulation of such Spread spectrum signal hidden by carrier signal. The simulation results show that the BER of this the algorithm is close to the theoretical line performance, and it can be efficiently applied to the demodulation and engineering practice of the DVB-CID signal.