Abstract: Underground pressure behavior characteristics of Guozhuang 2^nd Colliery＇s 2911 mining face under hard igneous rock were discussed by theoretical analysis，analog simulation and on-the-spot measurement.It was obtained that in gangue stowing，roof movement could be divided into immediate roof caving，immediate roof curving and subsidence，and hard roof subsidence.In gangue stowing mining under hard and thick roof，roof deflection was far smaller than non-contact value of stowing body，no force action between roof and stowing body.Measured support working resistance was generally smaller than rated value by statistic analysis.Separation development before hard roof broken took on repeating separation and compaction characteristic，and separation of every time would larger than that of previous time.