Abstract: To solve the problem that the signal received by a non-cooperative receiver in communication reconnaissance is interfered by co-channel signals, a new algorithm based on cyclic spectrum amplitude was proposed to estimate the carrier frequencies and chip width of multi-signals. This algorithm is suitable for signals with low SNR (signal-to-noise ratio) and can implement blind estimation without prior knowledge of pseudorandom sequences, and it avoids the impact and interference of stationary noises by searching in nonzero cyclic frequencies. The simulations indicate that when the power ratio is 1 to 1, the correct probability of carrier frequencies can reach 100% for SNR=-9 dB, and the correct probability of chip width can reach 99% for SNR=-4 dB.