Abstract: Time Varying Enhancement (TVE) is an important technology to deal with multipath fading often encountered in communication and measurement using electromagnetic wave, sound or laser. The self-focusing function of Time Reversal Mirror (TRM) makes it effective in blind TVE by realizing the thought of TVE automatically. Iterative Passive TRM (IPTRM) further strengths its TVE competence by using iterations. This study illustrated and analyzed the principle of TVE of IPTRM for the multipath signal in mathematics, presented the formulas of Gain Ratio and its times in 2nd IPTRM and also simulated and discussed the characteristics of IPTRM in both TVE and noise-removing. Based on the characteristics, study further pointed out the optimal selection of interesting part in IPTRM result and the method to select optimized original gain ratio, so that to get more remarkable TVE without any decreasing the SNR promotion. Contrasted to the present ways of TVE, IPTRM in this study is more simplified and practicable by realizing blind TVE and de-noising at the same time. It is much better that the TVE’s performance can be controlled by simply changing the original gain ratio in estimated channel.