Abstract: Due to the limitation of product sales and surrounding environment,underground mining method is adopted in a quartz sand mine.The ore body is close to the ore boundary in the south and west，ensure the safety of the ore body in the process of mining,it is necessary to reserve the safety pillar in the ore section near the ore boundary.Therefore,FLAC3D numerical simulation software was used to analyze and compare the safety and stability of security pillars with different thicknesses for ore body mining,and finally determine the reasonable size of security pillars.

Key words: Quartz sand mine,Safety pillar,Numerical simulation,Stability analysis