The definite geological environment and complicated in-situ stress field in deep have important influence on the mechanical properties of deep rock mass.Wanfu Coal Mine is located in the juncture of Juye County and Chengwu County in the south-west of Shandong Province,China.The overburden soil layer in the mine is over 700 m thick.The in-situ stress measurement in the mine is carried out to provide accurate in-situ stress condition and its attribution law.Based on these and according to the ground pressure environment of different sandstone at more than 900 m depth in Wanfu coal mine field,the effects of deep in-situ stress condition on mechanical properties of sandstone are studied by using triaxial rock mechanics experimental system,and the relative relationships between the mechanical properties of sandstone and confining pressure are established.It is shown that the stiffness and strength of the sandstone increase with confining pressure increasing;and under lower confining pressure,shear failure occurs while under higher confining pressure plastic fluent failure occurs.