A structure for adjusting a support force of a lumbar pillow, comprising: a backrest bracket, a lumbar pillow, an elastic support, and an adjustment mechanism; wherein a top of the lumbar pillow is flexibly connected to a front side of the backrest bracket; one end of the elastic support is connected to a back of the lumbar pillow, and the other end of the elastic support is provided with a slider, the slider being provided with an internally threaded hole; the adjustment mechanism comprises a lead screw, wherein the lead screw runs through the internally threaded hole, the lead screw is rotatably connected to the backrest bracket, and an extension direction of a rotation axis of the lead screw with respect to the backrest bracket is consistent with a vertical direction of the backrest bracket; and in response to the lead screw rotating with respect to the backrest bracket, the slider slides upward and downward along the vertical direction of the backrest bracket to change a support angle of the elastic support for the lumbar pillow, such that a magnitude of the support force of the elastic support to the lumbar pillow is adjusted, characterized in that the adjustment mechanism further comprises a horizontal rotation shaft; wherein the horizontal rotation shaft is rotatably connected to the backrest bracket, two ends of the horizontal rotation shaft extend along a widthwise direction of the backrest bracket and are each fixedly connected to a handle, the handle being disposed outside the backrest bracket, and a middle portion of the horizontal rotation shaft is provided with a driving bevel gear; and one end of the lead screw is provided with a driven bevel gear, wherein the driven bevel gear is meshed with the driving bevel gear, and the lead screw is arranged to be perpendicular to the horizontal rotation shaft. a top of the lumbar pillow is flexibly connected to a front side of the backrest bracket; one end of the elastic support is connected to a back of the lumbar pillow, and the other end of the elastic support is provided with a slider, the slider being provided with an internally threaded hole; the adjustment mechanism comprises a lead screw, wherein the lead screw runs through the internally threaded hole, the lead screw is rotatably connected to the backrest bracket, and an extension direction of a rotation axis of the lead screw with respect to the backrest bracket is consistent with a vertical direction of the backrest bracket; and in response to the lead screw rotating with respect to the backrest bracket, the slider slides upward and downward along the vertical direction of the backrest bracket to change a support angle of the elastic support for the lumbar pillow, such that a magnitude of the support force of the elastic support to the lumbar pillow is adjusted, characterized in that the adjustment mechanism further comprises a horizontal rotation shaft; wherein the horizontal rotation shaft is rotatably connected to the backrest bracket, two ends of the horizontal rotation shaft extend along a widthwise direction of the backrest bracket and are each fixedly connected to a handle, the handle being disposed outside the backrest bracket, and a middle portion of the horizontal rotation shaft is provided with a driving bevel gear; and one end of the lead screw is provided with a driven bevel gear, wherein the driven bevel gear is meshed with the driving bevel gear, and the lead screw is arranged to be perpendicular to the horizontal rotation shaft.