Abstract: Optimizing detection performance of passive sonar is important in sonar signal processing.The focusing effect of the single time reversal mirror(TRM) in multi-path channels is proved by simulation and the technique of passive iterative TRM is studied.The selective focusing and locating of TRM are studied while multi-targets exist.The results show that the passive TRM can realize the multi-targets′ space matched-filtering,and combined with iterative algorithm the passive iterative TRM can be focused on the most reflective target and weaken environment noise.