Abstract: The domestically-made safety distributed control system（DCS） was first applied to the large-scale sodium cooled fast reactor, and its reliability is very important to the safety of reactor. For large-scale sodium cooled fast reactors, a fault tree analysis method independent of the designer’s Markov analysis method is used to select the rejection probability of the emergency shutdown system in the protection system for review and review calculations, and establish a fault tree reliability calculation analysis model, example calculation and analysis,and comparison with the reliability calculation results provided by the designer. The results show that the relative deviation between the rejection probability calculation results of the emergency shutdown system in the safety-level DCS protection system and the designer’s calculation is within 8%. The calculation results of the two methods meet the requirements of the technical specifications, indicate that the designer’s calculation is effective and credible, it provides technical support for the nuclear safety review of the safety-level DCS of the large-scale sodium cooled fast reactor.