The invention discloses a large-flow proportional directional valve, and belongs to the technical field of hydraulic pressure. The large-flow proportional directional valve comprises a valve body anda valve element assembly, wherein the valve element assembly is slidably arranged in the valve body in the direction of the center line of the valve body; the valve element assembly comprises a firstpiston rod and two first piston parts, and the two first piston parts are coaxially arranged on the first piston rod at intervals in the central line of the first piston rod; the two first piston parts comprise supporting rings and piston walls; for the two first piston parts, a plurality of throttling openings are formed in the outer edge of the first end of the piston wall, and each throttling opening is arranged in a circumferential direction by taking the center line of the piston wall as an axis; each throttling opening comprises a first hole section, a second hole section and a third hole section, wherein the first hole section, the second hole section and the third hole section are arranged in sequence in a communicating mode; the first hole section is an oval hole, the second holesection is a long-strip-shaped hole, and the third hole section is a variable-section hole; and the sectional area of the third hole section is gradually reduced from the first end of the piston wallto the second end of the piston wall. The proportional characteristic of the large-flow proportional directional valve is ensured.