The invention discloses a water-retaining method for frozen peeled shrimps, which comprises the following steps of: removing heads and shells of shrimps, sterilizing with ozone water with the ozone concentration of 1-1.5mg/L for 1 to 5 minutes, and controlling the temperature of the ozone water below 10 DEG C; taking the peeled shrimps out, soaking in sterile water containing 0.5 to 0.45 mass percent sodium chloride, 0.25 to 0.75 mass percent food-level trehalose and 0.5 to 1.5 mass percent sodium alginate lysate for 30 to 50 minutes, controlling the water temperature at about 4-10 DEG C and the water amount 1.5 to 2 times weight of the peeled shrimps, taking the peeled shrimps out, and freezing until the core temperature is below -18 DEG C to obtain the frozen peeled shrimp products. In the method, a phosphorus-free water-retaining agent is adopted to process the peeled shrimps for the first time to fulfill the aim of retaining water; and the technology changes the traditional phosphate water-retaining process for the frozen peeled shrimps, solves the problems of water loss and color change in the freezing storage process, avoids the unpleasant metal astringency of the peeled shrimp products and unfavorable human health events caused by the conventional phosphate water-retaining agent, improves the quality appearance and price of the peeled shrimp products, and promotes the economic benefit of the peeled shrimp products.