Channel estimation is the premise for receiver to compensate the channel in the SC-FDE system. Aimed at the problems that particle weight degradation exists in the PF algorithm of the classic estimation algorithm of the system in combination with the PSO algorithm, a timeC-varying channel estimation method for SC-FDE system based on particle swarm optimization and improved PF algorithm is proposed. On the basis of analyzing the SC-FDE system communication principle and the establishment of the channel estimation dynamic space model, the principle of particle filtering is analyzed, the idea of PSO algorithm is introduced, the random particle sequence is obtained through Logistic mapping, and the PSO algorithm is used to improve the particle distribution area. Use MATLAB software to compare the PSOC-PF algorithm with LS algorithm, EKF algorithm, and DFT algorithm. The simulation results show that compared with other traditional channel estimation algorithms, the PSOC-PF algorithm has lower BER and NMSE both in Gaussian noise channel and in nonC-Gaussian noise channel environments, and better performance in a slow timeC-varying channel environment.