Abstract: Based on the actual background of the filling mining project in Datang section of Wengfu Phosphate Mine，focusing on the stability control of the overlying filling body in the stope，the technical idea of ensuring the stability of the filling body and the safe recovery of the pillar by leaving the top pillar （ore body）is put forward. Combined with the actual geological conditions of the mine，four groups of dif⁃ ferentiated mining schemes are designed，and 0，1，2，3 m top pillars are set up respectively. From the three core dimensions of displacement field evolution，stress field distribution and plastic zone develop⁃ ment，the stability characteristics of the overlying filling body under each scheme are systematically com⁃ pared and analyzed. The results show that when it is mining with 0 m top pillar，there are significant dis⁃ placement deformation and strong stress concentration in the overlying filling body of the goaf，and the plastic zone is easy to penetrate，which seriously threatens the stability of the filling body. After retaining the top column，the displacement deformation，stress concentration and plastic zone development range of the filling body are significantly improved，and the improvement effect gradually increases with the in⁃ crease of the thickness of the top column. Among them，the scheme of leaving 2 m top pillar has the best performance，which can not only maintain the integrity of goaf morphology and effectively inhibit the insta⁃ bility and failure of filling body，but also take into account the high ore recovery rate and achieve the engi⁃ neering goal of safe and efficient recovery of pillar. This study provides a direct engineering basis for the op⁃ timization of top pillar parameters in filling mining method of similar phosphate mines，and has important practical guiding significance for improving mining safety and resource utilization efficiency.

Key words: subsequent filling, top pillar, filling body stability, collaborative mining, numerical sim?ulation