The utility model relates to an elastic seal pair of a gate valve, belonging to the technical field of gate valves. The elastic seal pair of gate valve is characterized in that a nitrile butadiene rubber layer is wrapped outside the gate valve, the bottom of the nitrile butadiene rubber layer is an arc projection, and an oblique projection is arranged on the nitrile butadiene rubber layer at the connection part of the lower turned part of a gate disc with the valve body. Compared with the prior art, the elastic seal pair of gate valve has the advantages that protective projections are arranged at the easily worn parts of the rubber layer; when pressure is exerted on the rubber layer, the compression degree of the projection parts is gradually reduced toward the boundary lines at the two sides, and the seal surface width is uniformly expanded, so synchronous seal is formed, and seal effect is improved.