Reliability is an important factor in the design, operation and maintenance of an intelligent substation. For the two time in smart substation protection system reliability evaluation system is not perfect, the two protection of intelligent substation to state division, which is based on the Markov model of the reliability evaluation of two intelligent substation system model. The influence of the repair rate on the system failure rate is analyzed by means of an example. The results show that increasing the restoration rate can reduce the two system failure rate of the intelligent substation, and thus improve the reliability of the system.