The invention discloses a flow regulator for the mud suction pipe of a self-suction type suction dredge. The regulator is composed of a regulator outer cylinder and a regulator inner cylinder which are nested in a radial direction. A flange inside the regulator inner cylinder is welded to fix on the bottom surface of a mud collecting groove, and is in connection with the upper end flange of the mud suction pipe orifice. The top part of the regulator outer cylinder is provided with a positioning circular ring and a slender rod which is welded along the diameter direction; and a trapezoid water outlet is arranged on the outer cylinder wall. A flange is arranged at the bottom of the regulator inner cylinder, and a rectangular water outlet is arranged on the inner cylinder wall. The waist center lines of the two water outlets are superposed after assembling. The positioning circular ring of the regulator outer cylinder is in clamped connection with the upper orifice of the regulator inner cylinder. The flow regulator of the invention achieves the aims of regulating the mud water flow in the mud suction pipe and controlling the mud-suction flow through rotating to regulate the discharge area of the water outlet. The flow regulator is simple in structure, convenient in processing and easy to maintain, and can be dismantled conveniently and fast, greatly reducing the workload of pipeline dredging.