Abstract: To solve the problem of the fault protection coal pillar in deep mining and aiming at the shortcomings of the traditional empirical formulas, the main factors affecting the fault protection coal pillar's stability are screened by the analytic hierarchy process. By numerical simulating of the protection coal pillar under different conditions, its width under the critical state of the fault activation is obtained. The result proves that the traditional empirical formulas are weak adaptability. MATLAB regression analysis shows that the protective coal pillar's width has good fitting effect and better correlation with the formula of different factors.