Abstract: Aiming at the coal pillar type impact instability caused by high ground stress caused by thick roof rock, large reserved width of coal pillar and buried depth of 500 ~ 700m in Ordos mining area, a mechanical model for calculating the internal stress of coal pillar is established, and the coal pillars with different stress performance characteristics are classified and discussed. The internal stress of components is calculated based on the superposition principle of elastic mechanics combined with rock mechanics and material mechanics, The calculation formula of the maximum and minimum intermediate principal stress is derived after the conversion of the three-dimensional stress at any position in the coal pillar. Secondly, taking the 3102 working face of menkeqing coal mine as the background, the theoretical calculation and FLAC3D numerical simulation experiment are carried out, and the accuracy of the deduced calculation formula of coal pillar internal stress is verified based on the field measured data. Finally, the critical starting conditions of coal pillar type rockburst obtained according to the internal stress calculation formula can be used as an effective measure and means to guide the on-site prevention and control of the impact phenomenon caused by the high internal stress of coal pillar.