Abstract: With 3213，3214 working face of protective layer in Liangzhuang Coal Mine as the engineering background，the pressure relief mechanism of upper protection layer is analyzed.In order to determine the protection scope of the lower coal seam after upper protective layer mined.FLAC3D numerical simulation software was used to simulate the protective layer mining under actual geological conditions.Research shows that：with the increase of mining scope of protective layer，a certain range of coal strata on the floor is showing as in pressure relief at internal goaf with obvious effect in pressure relief zone.The range of pressure relief zone increases gradually.The stress distribution shows as the “U” type gradually from “V” type.Stress concentration at the boundary is gradually increased，and its peak stress and range is also increased；Through the comprehensive experience method and the pressure relief criteria，a reasonable arrangement of 3414 working face was determined.The open-off cut located at 19 m from 3414 working face internal misaligned with 3214 working face，the mining line stopped at 19 m，and the coal lane is at 17 m in turn.

Key words: Upper protective layer, Pressure relief mechanism, Protection scope, Numerical simulation