As a major risk source, slope in open-pit coal mine is one of the main challenges faced by mine safety production. Taking Wanyuan open-pit coal mine in Wuhai City, Inner Mongolia Autonomous Region as an example, based on detailed investigation of slope development characteristics, deformation and failure modes were analyzed, slope radar deformation monitoring was carried out, and early warning models were established, a monitoring and early warning platform was built to achieve risk control. The results show that the slope of Wanyuan open-pit coal mine involves reverse, cross and consequent rock slope and soil slope of dump, and its deformation and failure modes are respectively tensile fracturing, wedge failure, slip-bending and creep (-tensile cracking). There is a possibility of instability under the influence of mining, blasting, rainfall or unreasonable stacking. On this basis, in order to realize the monitoring of slope without blind area, two sets of slope radar were respectively installed at the stable bedrock on the northeast and southwest sides of the mine, and the slope safety grade was divided into four grades: blue (<3 mm/h), yellow (3~8 mm/h), orange (8~15 mm/h) and red (>15 mm/h). Combined with the organizational structure of mining enterprises, the slope safety management system from slope radar deformation monitoring data-early warning model-early warning platform-risk management and control are constructed, which can provide technical reference for the construction of regional coal mine safety production capacity.