The present invention relates to a seasoning product and more particularly relates to a freshwater mussel juice and a preparation method, and belongs to the technical field of food processing. The preparation method uses freshwater mussels as raw materials and capsella bursa-pastoris, asparagus lettuce, shii-takes, shallots, gingers, etc. are added, and the raw materials are brewed into the fresh mussel juice. The freshwater mussel has efficacies of clearing heat and causing diuresis, relieving swelling, etc. The capsella bursa-pastoris can improve eyesight and clear heart, and benefit intestines and relax whole body. Chinese yams can tonifying qi and supplementing kidneys, and enhance resistance. The prepared freshwater mussel juice is added in an appropriate amount during dish cooking, so that the original light taste is added with a unique flavor. In addition, the prepared freshwater mussel juice is safe, healthy, and in line with people's tastes for truth and freshness.