Abstract: A complete system of reliability design of grouting for stopping water in rock mass was established in this paper. Fault tree of grouting for stopping water and simplified successful tree were drawn. Limit state equation of basic events were found. Calculation models of logical relation and calculation methods of reliability for first grouting, repetitive grouting, auxiliary grouting of single hole and multiple hole grouting system were established. Working states and security grades of grouting system were defined. Reliability indexes of different grouting projects were given. Reliability design method and process of grouting were given. It can instruct design and construction of grouting projects in site, and has important theoretical value and wide application prospects.