A behavior of ridge-cut rock slope had been monitored by installing inclinometers and regional slope movement toward rear side of cut face was detected. To delineate the governing factors of slope behavior, especially backward slip of ridge-cut slope, petrographic characteristics of rock cores obtained from four drilled boreholes had been examined. BIPS images inside boreholes had been acquired and structural characteristics of slope rock had been studied. Mechanical properties of discontinuity planes distributed in the drilled core had been measured and the shear strength of coal seam imbedded-discontinuity planes also had been obtained by performing the direct shear test. Monitoring results of slope behavior had been analyzed by comprehensibly considering both the mechanical and structural characteristics of slope rock and coal seam-imbedded discontinuity planes, and the potential governance of coal seam and clay minerals embedded in the joint plane on the regional slope behavior has been also identified.