Abstract: The stability of underground surrounding rock is an important factor that affect mining design and safe production.The stability of surrounding rock is affected and restricted by many factors，and many of these factors are uncertain， non-linear， and hidden.Can not be quantified，Therefore，it brings challenges to the stability evaluation of surrounding rock.In order to evaluate the stability of the surrounding rock of an underground tantalum niobium mine in Jiangxi Province accurately and scientifically，a comprehensive model for the stability evaluation of the surrounding rock of the 417 m middle section of the mine is established by using the unascertained measurement theory.The subjective and objective weights calculated by the G_1 method and the entropy method are optimized by using the difference coefficient method，and the comprehensive unascertained measure of the evaluation object is determined.Combined with the actual situation of the mine，considering the influencing factors，six factors are taken as the evaluation indexes:rock quality designation （RQD），rock uniaxial compressive strength，rock integrity coefficient，in-situ stress，gap wall state and groundwater state.Qualitative evaluation shows that the stability grade of the surrounding rock in the middle 417 m is grade III（basically stable）.The study results can provide some guidance for the future mining design and construction of the mine.

Key words: Underground mining, Stability of surrounding rock, Stability evaluation, Uncertainty measurement, G_1 method, Entropy method