The invention belongs to the technical field of health-care tea beverages and relates to a preparation method of seaweed tea capable of improving the immunity. The method comprises the following steps: sorting seaweeds, removing impurities, washing, fishing out, naturally drying, grinding into small pieces, and drying at constant temperature for later use as raw materials; removing jujube pits, washing, drying, cutting into strips, and drying in a drying oven for later use; burning cornu gorais at controlled temperature to be burnt black and grinding into powder for later use; processing blumea camphor, almonds, asarum forbesii maxim and monkshood, grinding, and screening by a 30-60-mesh sieve for later use; weighing seaweed raw materials and auxiliary materials according to a weight ratio, fully mixing, and drying at the constant temperature for aroma extraction; finally packaging by 5-15g per bag, vacuumizing, sealing, and boxing for storage. The preparation method is scientific and sanitary, a formula is unique, the tea does not have toxic and side effects, the raw materials are natural and green, and the finished tea is fragrant in taste.