Abstract: Fuzzy comprehensive evaluation is an effective method to evaluate the quality grade of rock mass.The traditional fuzzy comprehensive evaluation method is one-sided for the weight assignment，and mostly uses the principle of maximum membership degree to make decisions，which may result in the loss of data information and the lack of persuasion.In order to solve this problem，the entropy weight method is proposed to determine the weight coefficient，and the maximum membership principle in the traditional method is modified by calculating the effectiveness， so as to establish an improved fuzzy comprehensive evaluation model. Selecting uniaxial saturated compressive strength， integrity coefficient， rock basic quality index (RQD)，structural plane influence coefficient and groundwater influence coefficient as evaluation indexes，the improved fuzzy comprehensive evaluation model is applied to rock mass quality evaluation of No.2 roadway in Jinchang mining area of Yinan Gold Mine.The results show that the surrounding rock is poor as a whole，between grade Ⅳ and grade V.Compared with the results of traditional fuzzy comprehensive evaluation method and BQ classification method，it is found that the improved fuzzy comprehensive evaluation method is more close to the results of BQ method，and solves the disadvantages of traditional fuzzy comprehensive evaluation method and BQ method， and obtains more scientific and reasonable classification results.In view of this result，the supporting measures of shotcreting，laying metal mesh and bolt are put forward to ensure the integrity and stability of surrounding rock.

Key words: Fuzzy comprehensive evaluation method, Entropy weight method, Classification of rock mass quality, Maximum membership principle, Validity