A folding mechanism, comprising: a shaft base; a support (332, 333), comprising a main body (3323, 3333) and a revolute pair (3324, 3334), wherein the revolute pair (3324, 3334) is fixedly connected to the main body (3323, 3333), and rotatably connected to the shaft base; a support plate (335, 336), comprising a main plate (3352, 3362) and a kinematic pair (3353, 3363), wherein the main plate (3352, 3362) comprises a first plate edge (3352-3, 3362-3) and a second plate edge (3352-4, 3362-4) that are disposed opposite to each other, and when the folding mechanism is in an unfolded state, the first plate edge (3352-3, 3362-3) and the second plate edge (3352-4, 3362-4) are arranged in a first direction; and the kinematic pair (3353, 3363) is fixedly connected to the main plate (3352, 3362), and comprising a rotating structure and sliding structure, the kinematic pair being rotatably connected to the main body (3323, 3333) by the rotating structure, and slidably connected to the shaft base by the sliding structure, the sliding structure being configured to permit slidable rotation between the kinematic pair and the shaft base; and a door plate that can move relative to the shaft base in a second direction, wherein the second direction is perpendicular to the first direction, and in the unfolded state, the second direction is perpendicular to a plane on which the main plate (3352, 3362) is located, wherein in the unfolded state, the support plate (335, 336) and the door plate are arranged side by side in the first direction and form a support surface (3351, 3341, 3361) for supporting a flexible display, the first plate edge (3352-3, 3362-3) is adjacent to the door plate, and a spacing between the first plate edge (3352-3, 3362-3) and the door plate in the first direction is a first dimension; and in a folded state, the spacing between the first plate edge (3352-3, 3362-3) and the door plate in the first direction is a second dimension, and the second dimension is greater than the first dimension to completely close a first frame body and a second frame body fixedly connected to the support (332,333) and supporting the flexible display. a shaft base; a support (332, 333), comprising a main body (3323, 3333) and a revolute pair (3324, 3334), wherein the revolute pair (3324, 3334) is fixedly connected to the main body (3323, 3333), and rotatably connected to the shaft base; a support plate (335, 336), comprising a main plate (3352, 3362) and a kinematic pair (3353, 3363), wherein the main plate (3352, 3362) comprises a first plate edge (3352-3, 3362-3) and a second plate edge (3352-4, 3362-4) that are disposed opposite to each other, and when the folding mechanism is in an unfolded state, the first plate edge (3352-3, 3362-3) and the second plate edge (3352-4, 3362-4) are arranged in a first direction; and the kinematic pair (3353, 3363) is fixedly connected to the main plate (3352, 3362), and comprising a rotating structure and sliding structure, the kinematic pair being rotatably connected to the main body (3323, 3333) by the rotating structure, and slidably connected to the shaft base by the sliding structure, the sliding structure being configured to permit slidable rotation between the kinematic pair and the shaft base; and a door plate that can move relative to the shaft base in a second direction, wherein the second direction is perpendicular to the first direction, and in the unfolded state, the second direction is perpendicular to a plane on which the main plate (3352, 3362) is located, wherein in the unfolded state, the support plate (335, 336) and the door plate are arranged side by side in the first direction and form a support surface (3351, 3341, 3361) for supporting a flexible display, the first plate edge (3352-3, 3362-3) is adjacent to the door plate, and a spacing between the first plate edge (3352-3, 3362-3) and the door plate in the first direction is a first dimension; and in a folded state, the spacing between the first plate edge (3352-3, 3362-3) and the door plate in the first direction is a second dimension, and the second dimension is greater than the first dimension to completely close a first frame body and a second frame body fixedly connected to the support (332,333) and supporting the flexible display.