The invention relates to a stair rail chair. The stair rail chair comprises a movable seat body, a seat is fixedly connected to the vertical outer side wall of the movable seat body, a vertical pulley is arranged on the upper part of the vertical inner side wall of the movable seat body, and a wall-leaning pulley is arranged on the lower part of the vertical inner side wall of the movable seat body; the vertical pulley is embedded into a first inclined groove in the top of a enclosing wall surface of a stair, and the wall-leaning pulley is embedded into a wall-leaning inclined groove in the inner side wall of the enclosing wall surface of the stair; an annular sliding frame is hinged to the top of the movable seat body through a stand column, wherein a handrail rod above the enclosing wall surface of the stair penetrates through the sliding frame, and idler wheels used for being embedded in a second inclined groove in the handrail rod are arranged on the sliding frame. The stair rail chair is simple in structure.