Abstract: The single sensor Passive Time Reversal Mirror (PTRM) is introduced which could match the acoustic channel automatically and lead to an adaptive focusing. PTRM is applied to Pattern Time Delay Shift Coding (PDS) that is called PTRM-PDS underwater acoustic communication system. The results of computer simulations and lake trials show that the PTRM-PDS system could mitigate the ISI caused by acoustic channel's multipath and adapt to spatial-temporal variant channel robustly with low bit-error-rate.