Abstract: Under the framework of RMPS（Reliability Methods for Passive Safety Functions）, thermal-hydraulic reliability（TH-R） of an experimental facility is evaluated, and sensitivity analysis is applied for uncertainty parameters which has effects on the TH-R of the passive systems. Related conclusions contribute to understand the uncertainty of the thermal hydraulic processes of the passive residual system from the view of reliability. Results of reliability and sensitivity analysis can be used to guide the system optimal design and operation management.