In order to guarantee the slope safety of coal mining in Baiyinhua No.1 open-pit mine, a reasonable angle of slope has been determined and slope stability has been analyzed and evaluated. On the basis of careful analysis on engineering geology, hydrogeology, slope rock's physical and mechanical properties of materials actually exposed layer of each section, combining the past landslides for the No.1 open-pit in Baiyinhua, using slope numerical calculation software FLAC^3D, the slope stability of No.1 open-pit in Baiyinhua is analyzed and researched in detail, then the reasonable slope angles for the No.1 open-pit mine in Baiyinhua are identified. At the same time, the effects on slope stability for refuse dump inward open pit mines are researched to track in the mining process. The results show that a reasonable distance from the inner row of track might increase slope angle. It is feasible to improve coal recovery in the open-pit mine. A theoretical basis is provided for the open-pit mining in Baiyinhua.