A steel ball concealable three-section slide rail structure, wherein the steel ball concealable three-section slide rail structure comprises a top rail, a middle rail, a bottom rail and rolling members; the top rail and the middle rail are connected slidably and rolling members are provided between the top rail and the middle rail, and the middle rail and the bottom rail are connected slidably and rolling members are provided between the middle rail and the bottom rail; the top rail is provided with a first insertion opening, the bottom rail is provided with a second insertion opening, and the first insertion opening and the second insertion opening are arranged opposite to each other; the middle rail comprises a first insertion portion, a transition portion and a second insertion portion connected in sequence; the first insertion portion is inserted into the first insertion opening to connect slidably with the top rail, the second insertion portion is inserted into the second insertion opening to connect slidably with the bottom rail; between the first insertion portion and the top rail and between the second insertion portion and the bottom rail are each provided at least three groups of rolling members, and the at least three groups of rolling members are arranged in an isosceles triangle viewed from a cross-section direction of the middle rail; wherein a top surface of the top rail is a mounting surface which is a flat surface; the first insertion portion and the second insertion portion have the same structure and each comprise a first positioning plate, a second positioning plate, and a third positioning plate that are connected in sequence; and the second positioning plate is substantially parallel to the mounting surface; the middle rail comprises a sliding cavity; the first positioning plate and the third positioning plate are both inclined toward the sliding cavity; the first positioning plate, the second positioning plate and the third positioning plate define a first mounting groove for mounting the rolling members, a second mounting groove for mounting the rolling members is defined on an outer side of the first positioning plate, and a third mounting groove for mounting the rolling members is defined on an outer side of the third positioning plate; a first accommodating cavity is defined in the top rail, a second accommodating cavity is defined in the bottom rail, and the first accommodating cavity and the second accommodating cavity each have a fourth mounting groove, a fifth mounting groove, and a sixth mounting groove that are respectively matched with the first mounting groove, the second mounting groove and the third mounting groove; the top rail is provided with a positioning assembly which comprises a first positioning member located at a front end of the top rail and a second positioning member located at a rear end of the top rail; the first positioning member comprises a first connecting portion connected to the top rail and substantially perpendicular to the mounting surface of the top rail; an end of the first connecting portion is provided with a second connecting portion which is substantially perpendicular to the first connecting portion and extends toward an inner side of the top rail; an end of the second connecting portion is provided with a first insertion positioning portion which extends perpendicular to the second connecting portion; and a top end of the first insertion positioning portion is provided with a first positioning portion which forms a first angle α with the first insertion positioning portion, where 90° < α < 180°; and the second positioning member comprises a third connecting portion substantially perpendicular to a top end of the top rail, a top end of the third connecting portion is provided with a second insertion positioning portion along an extension direction of the top rail; an end of the second insertion positioning portion is provided with a second positioning portion which is disposed along the extension direction of the top rail; and the second positioning portion and the second insertion positioning portion form a second angle β, where 90° < β < 180°.