A　reasonable　and　stable　stope　structure　is　the　premise　of　realizing　safe　mining　of　underground　metal　ore.　To　safely　mine　the　gently　inclined　medium-thick　ore　body,　stope　stability　in　Bainiuchang　Mine　was　analyzed　based　on　the　pillar　area　bearing　theory,　and　stope　stability　with　regard　to　nine　groups　of　structural　parameters　was　numerically　simulated.　The　results　show　that　the　existing　stope　structural　parameters　failed　to　maintain　stability　requirements　and　tended　to　be　exposed　to　the　risk　of　stope　collapse.　The　middle　section　of　the　pillar　as　well　as　stope　roofs　and　floors　are　vulnerable　due　to　tensile　stress　when　mining　by　open　stoping,　and　the　compressive　stress　concentration　is　prone　to　occur　at　the　junction　of　the　pillars,　stope　side　walls,　roofs　and　floors.　Shear　stress　contributes　little　to　pillar　failure.　The　reasonable　stope　structural　parameters　of　open　stoping　for　the　gently　inclined　medium-thick　ore　body　in　Bainiuchang　mine　are　optimized　using　ANSYS　numerical　simulation:　stope　height　4.5　m,　pillar　diameter　4　m,　pillar　spacing　7　m　and　pillar　row　spacing　8　m.　The　onsite　trial　shows　that　the　ore　recovery　rate　reaches　82%　under　these　parameters,　which　also　realizes　the　equilibrium　of　safety　and　economy.　©　2022　by　the　authors.　Licensee　MDPI,　Basel,　Switzerland.