Abstract: ［Objective］ Rail transit safety hosts are the core of the train operation control system, and it is necessary to conduct safety research on the rail transit safety hosts. ［Method］ The system architectures of the 2-out-of-3 safety host and the double 2-vote-2 safety host are introduced. A quantitative calculation method for the safety hosts that combines Markov method and GO method is proposed and verified through actual example. ［Result & Conclusion］ Within the same working period, the safety of the power module decreases the fastest. So in practical applications, special attention should be paid to the safety of the power module in the safety hosts. In the initial working period, the security performance of the double 2-vote-2 safety host is higher than that of the 2-out-of-3 safety host, but the difference in security performance between the two safety hosts is not significant; with the increase of working time, the security performance of both safety hosts decreases. Adoption of the proposed Markov-GO joint model can achieve safety quantitative analysis of the safety hosts.