Abstract: Owing to its deficiency in considering influence factors of deep rock mass quality and determination of evaluation index values, the traditional RMR method has many limitations in the quality evaluation of deep mining rock mass. The marking indexes including uniaxial compressive strength of rock, rock quality designation, joint space and in-situ stress in traditional RMR method are firstly revised by calculation method of continuous thinning, regression curves and continuity equations between evaluation indexes and score values are obtained. Secondly, based on the analysis of bad geological factors and deep mining technology influence in rock mass quality, two new indexes including blasting vibration effect coefficient and stope exposed area are put forward; furthermore, M-IRMR evaluation system is established. Finally, the M-IRMR method is applied to the rock mass quality evaluation of Sanshandao gold mine which is a deep mining mine near coast. Achieved results will provide certain guiding significance to stability evaluation of rock engineering in deep mining mine.