The invention provides blended clam sauce and a preparation method thereof. The blended clam sauce is prepared by taking sweet soybean sauce as a basis, and adding clam broth powder, clam meat powder and clam Maillard product powder during post-blending. The preparation method comprises the following steps: preparing the sweet soybean sauce at first, and then adding 3-9% of the broth powder, 4-9% of the clam meat powder and 2-6% of the clam Maillard product powder, and adequately stirring to obtain the blended clam sauce. The blended clam sauce provided by the invention has the advantages that the product has strong seafood flavour and prominent delicate flavour, and the sauce body is brown and rich in flavour substances such as glutamic acid and aspartic acid. With the adoption of the preparation method of the blended clam sauce provided by the invention, the problem that clams cannot be stored for a long time is solved, the broth after cooking the clams is sufficiently utilized, the waste of raw materials is avoided, the nutrition and the health functions of grains and the clams are integrated, and natural delicate flavour in the clams is integrated in the traditional sauces.