The mechanical configuration and reliability design of its distributed computer control system for the big shoctcrete robot(RPJ-D) are introduced. But the latter is the emphasis of this paper. In RPJ-D's control system, the technologies of fault-tolerance, fault diagnosis and resisting the severe environment resistance are used. The high reliability design of its planning level and control level is realized by adopting different forms of redundancy configuration. Field-application indicates that the robot could meet the requirements of the work in wicked circumstances completely.