Abstract: According to the special structure of China Mobile Multimedia Broadcasting (CMMB) signal, this paper presents two methods for reference signal extraction in passive bistatic radar system based on CMMB signal, the adaptive filter algorithm based on the sync signal of CMMB and the method of reference signal reconstruction based on the theory of modulation and demodulation for CMMB signal. The specific processes of the two proposed algorithms are studied first. And next, the performance of the two methods in the typical multipath environment is compared though simulation and real data verifies the effectiveness of the reconstruction method. Analysis demonstrates that signal reconstruction method can eliminate the multipath clutter and interference in the reference signal more effectively, which indicates that this method can extract the reference signal with high purity and the algorithm is more robust.