Abstract: In order to guarantee the reliability and security of the microsurgery robot system, the idea of applying the HISIC (hazard identification and safety insurance control) and FTA (fault tree analysis) safety analysis methods to the system design is put forward. According to the demand of surgery environment and surgical operation, the authors make the research on how to use the following sequence: system demand analysis, hazard identification, safety insurance control, safety critical limits, satety monitoring control, verification and validation, system log and documents as the guide of the system design, and also make the research on how to use the fault tree and fault function to analyze the conclusion of design. The experiment of the prototype machine manifests that the two method' s integration can guarantee the reliability and security of the cornea grafting microsurgery robot system.