The invention provides a cross sectional settling tube with dredging plates for roadbeds of roads, and belongs to the technical field of road construction monitoring. The cross sectional settling tube comprises a sectional settling tube, detachable fixed pulley assemblies, connection type steel stranded pull wires, the detachable dredging plates and detachable hooks. The connection type steel stranded pull wires and the detachable hooks are matched with one another and are connected with an upper sectional settling instrument, the settling instrument can be pulled to move in the sectional settling tube, and the lengths of the pull wires can be increased or decreased according to engineering requirements. Each detachable fixed pulley assembly is fixed to an end of an orifice, a closed loop can be formed by the steel stranded pull wires in the tube, and the steel stranded pull wires can extend out of the same side of the cross sectional settling tube and are connected with one another. The detachable dredging plates are connected with the steel stranded pull wires and can pull the steel stranded pull wires, so that sundries settled in the cross sectional settling tube can be removed. The cross sectional settling tube has the advantages that new construction or extension engineering requirements of roads can be met, the work convenience can be improved for monitoring personnel, and the problem of inaccuracy of measurement data due to sludge in existing tubes can be solved; the cross sectional settling tube can be mounted quickly and conveniently and is favorable for field application and popularization.