In order to analyze reasonable mining width and coal pillar setting width of Caoduogou Mine, combined with theoretical calculation and numerical simulation, the recovery mining rate was 60% by theoretical calculation, coal pillar width 39 m, mining width 58.5 m, nuclear area rate of coal pillar 0.69, meeting the needs of theoretical design. Mining width 59 m by numerical simulation, pillar strength was reliable with 39 m coal pillar width, it was concluded that width of coal pillar was 39m, mining width 58.5 m.