Abstract: A new approach is proposed for single-channel blind separation of communication signal and time-varying amplitude LFM. The proposed algorithm aims to obtain the maximum a posterior (MAP) estimates of communication code and the unknown parameters using particle filtering by establishing the state space model for the interfered signal. Specially, in order to overcome the sample impoverishment problem and estimate iteratively the particles that have more important weigh, genetic operation is introduced to the re-sampling process in particle filtering. In such a way, the number of needed particles is reduced during the sequential estimation process. Simulation results of nonspread spectrum communication signal show that, the method is effective to separate communication signal and LFM interference when the Interference-Signal- Ratio (ISR) is less than 15dB and SNR is more than 16dB.