Abstract: A method for preparing a calcium-based metal-organic framework (Ca-MOF) for selectively adsorbing fishy off-odor compounds is disclosed. The method involves dissolving an organic acid and a calcium salt in an organic solvent, then transferring the solution to a high-pressure reactor for a high-temperature reaction. The solution is subsequently cooled to room temperature, followed by centrifuging, alcohol washing, and drying to yield Ca-MOF crystals. The resulting Ca-MOF demonstrates a selective and efficient adsorption of sulfur-containing compounds present in fishy off-odors, achieving up to a 97.3% removal efficiency for dimethyl trisulfide. With a fast adsorption rate, this Ca-MOF can be applied directly to food or used in an external sachet, making it suitable for diverse applications in food, medicine, and pesticides.