Abstract: For the caving method，the caving process of roof and surrounding rock，and the determination of displacement angle of stratum under caving mining，are always the focuses in the study of many scholars at home and abroad.Taking a hanging wall ore in Sichuan as engineering background，the variation of tension stress and plastic zone of roof under caving mining were simulated and analyzed by using software of MIDAS/GTS.The results showed that：the old main roof experienced tensile failure before the direct roof.Stress state of roof was improved significantly after the area of tensile failure of roof was caved forcedly；The area of tension stress of main roof and immediate roof，and of the tension failure of main roof extended significantly with the exposed area of immediate roof.But，the tension failure area of immediate roof wasn′t influenced evidently by it.Moreover，the displacement angle of stratum was determined by numerical simulation and engineering analogy method.

Key words: Hanging wall ore, Caving method, Roof, Surrounding rock, Exposed area, Displacement angle