Abstract: The ore-body in -95 m sublevel 4^# stope of Beiminghe Iron Mine is gently inclined medium thick ore-body，and the floor of ore-body is at unstable strata and the fissure grows in joint.Moreover，it has been bearing the mining pressure from adjacent stopes for two years.The side fall root caving appeared during the tunneling of cross roadway and stope or after tunneling.Although lots of compressible “U”-shaped metal arch are adopted in secondary support，but the drifts' deformation and destruction can't be controlled.Therefore，the pressure relief measures are used，obtaining remarkable effect.The paper described the depressurized mining experience of 4^# stope in detail，and discussed the parameters and the best time of pressure relief.

Key words: Mining pressure, High stress area, Depressurized mining