Abstract—With the analysis on the instability characteristics and inherent complications to tunnel surrounding rock during construction, the uniaxial compressive strength, rock quality indicator, rock integrity coefficient, structural plane intensity coefficient is chosen as the evaluation index about such instability, the decision-making hierarchical mechanism and regularizer matrix is erected on the basis of the integrated entropy information, variation coefficient and similarity coefficient from the above instability decision-making matix. Through the reasoning process and reckoning operation, the credibility and variability is obtained for the instability monitoring units, and the system accumulation effect evaluation is established on the overall surrounding rock instability, which finally carries on the overall evaluation about the surrounding rock security. Case shows that the model is provided with the scientific, simple and practical features in the surrounding rock instability operation and security evaluation work, whose result could fully reflect the synthesized stability situation about the surrounding rock.