Abstract: According to the mining conditions of Daizhuang Coal Mine, the stress and deformation of strip coal pillar in dynamic mining were analyzed by numerical simulation. In the dynamic mining, the stress peak value appears at the location of 4 m at the edge of the strip coal pillar and experiences the process of appearing, disappearing, and reappearing with the advancing of the working face. The stress of the strip coal pillar experiences slow, fast and slow process. The failure width of the strip coal pillar is 6 m. The deformation process of strip coal pillar was divided into 4 stages: slow compression stage, rapid expansion stage, deceleration transition stage and balance and stability stage. Rapid expansion stage is the main deformation stage of strip coal pillar, and 40% to 60% of total deformation is completed; the peak stress of coal pillar will have a great influence on the transverse deformation, and the deformation rate of the transverse deformation will appear inflection point.