Abstract: Designed and realized an ETMR system based on EHW and TMR technologies, and analyzed its reliability with Markov's course theory. We found that ETMR system has higher reliability compared with the single mould and TMR system in any times, and the main factor of influence the ETRM system reliability was the ratio of repair rate and failure rate, further, the larger the ratio is, the bigger the interval span that its reliability approach 1 is. This method and conclusions has certain inspiration and guidance in applying ETMR system to the concrete project practice.