The invention discloses long-acting moisture-keeping roe seasoning sauce and a preparation method thereof. The long-acting moisture-keeping roe seasoning sauce is prepared from the following raw materials in parts by weight: pigskin, table salt, baking soda, papain, white vinegar, snakehead roe, bay leaf, pickled Chinese cabbage, cardamom, star anise, Chinese prickly ash, chili oil, soybean sauce, white granulated sugar, grape juice, yellow rice wine and a proper amount of water. The invention belongs to the roe seasoning sauce; the seasoning sauce is mixed and coated with gelatin liquid extracted from the pigskin, and a very good gelatinizing effect is realized, so that the time for thickening the roe sauce in air is prolonged; meanwhile, a moisture-keeping capability of the sauce is improved, and a film forming effect is good; pigskin gelatin is used for replacing traditional gelatin, carrageenan and the like; trace amino acids in the pigskin gelatin have an auxiliary effect on umami; the source of the raw materials is wide, and the effect is obvious.