The invention relates to a preserving method for tropic water lily seedlings, and belongs to the technical field of seedling preserving and transporting. The method specifically comprises the following steps of 1, preparing a substrate; 2, planting tropic water lily seedlings through the substrate in step 1, maintaining the seedlings for 10-15 days in the full-sunlight exposure environment under the temperature of 25-35 DEG C, and keeping the water depth to be 5-7 cm in the maintaining period; 3, after seedlings survive and unfolded novel leaves grow from the rhizomes, stopping water supplementation, and lowering the maintenance temperature to 20-25 DEG C; 4, when water is evaporated till the water depth is 1-3 cm, further lowering the maintenance temperature to 15-20 DEG C, and not supplementing water till tropic water lily seedling leaves are withered, the substrate is shrunk and the surface layer of the substrate lacks water and is chapped; 5, taking out a substrate block containingtropic water lily seed balls, performing independent packaging and encasement, and placing the substrate block in the dry and cool environment to be preserved. The method is simple and easy to implement, the tropic water lily seed balls are preserved into the substrate block to achieve independent packaging, no water needs to be added for moisturizing, the seed balls can be preserved for 5-7 months, and storage, transpiration and later planting are convenient.