The invention discloses a proportional pressure-reducing valve, a proportional pressure-reducing valve bank, a suspension arm and a winding operation control system. The valve plug of the liquid proportional pressure-reducing valve is in stepped shaft shape and is composed of a minor-diameter section and a major-diameter section; a radial through hole is arranged on the minor-diameter section of the valve plug; an axial through hole which is communicated with the radial through hole is arranged on the external end face of the major-diameter section of the valve plug; the inner cavity of the valve body of the proportional pressure-reducing valve is provided with a minor-diameter section and a major diameter section which are matched with the valve plug in a sliding manner; the side wall ofthe valve body is provided with a first oil inlet, a second oil inlet and oil outlet in turn; the pressure oil which enters by passing the first oil inlet acts on the end face of the valve plug of the minor-diameter section; the pressure oil which enters by passing the second oil inlet acts on the annular stepped surface between the minor-diameter section and the major-diameter section, and flowsout from the oil outlet by passing an oil duct formed by the radial through hole and the axial through hole; the pressure of the first oil inlet is a constant value; and when the pressure of the second oil inlet is more than the constant value, the pressure of the oil outlet changes along with the changes of the pressure of the second oil inlet in a certain proportion.