In order to study whether a certain mine could guarantee the stability of the large-area continuous mining in the presence of a reserved 20 m-thick horizontal pillar,the horizontal pillar’s stress model was established,and then the criteria of horizontal pillar failure based on cusp catastrophe theory was deduced,ANSYS numerical simulation study was carried out,the evaluation index of the stability coefficient of the horizontal pillar was proposed,and the stability of the horizontal pillar was analyzed.The result shows that the stability of the horizontal pillar depends on the material properties and geometric dimensions set for the pillar,as well as the material property of the lower filling body,and the horizontal ground stress is a key external factor on the stability of the horizontal pillar;the first principal stress of the horizontal pillar is in the range of -4.2--33.2 MPa,and there is no possibility of stress concentration and tensile failure;the maximum value of the third principal stress and the equivalent principal stress appears in the Ⅶ panel,and the horizontal pillar stability coefficient exceeds 1.4,indicating high pillar stability.In the presence of reserved 20 m-thick horizontal pillar,the pillar can keep stable,which ensures safe and efficient mining in mines.The research results can provide guidance for similar mines.