The invention relates to a method for high-yield plantation of Salicornia and soil fertility improvement of coastal mud flat, which comprises the following steps: leveling mud flat salinized soil, furrowing and ditching; applying organic fertilizer into the mud flat salinized soil to fertilize soil; after applying the organic fertilizer into soil, sowing and earthing, which comprises mixing Salicornia seeds with fine sand and uniformly sowing the seeds into ditches; before emergence of seedlings of Salicornia, adopting seawater for irrigation, keeping the soil to be moist, and adopting seawater for irrigation within three weeks after the emergence of seedlings; after the three weeks after the emergence of seedlings, applying urea as topdressing, and applying fertilizer for three times during a growth period; and after applying fertilizer, immediately adopting fresh water for irrigation, after applying fertilizer during the growth period, adopting the fresh water for irrigation for three times, adopting the seawater for irrigation during other periods, and maintaining the soil to be moist. The method has the advantages that the yield of vegetables in salinized soil can be increased, and the nutrition quality is improved; the soil fertility cultivation of saline-alkali soil can be sped up, and the water sources can be saved; the raw materials has wide sources, and are easy to obtain; the development of coastal mud flat planting can be improved, the ecological environment can be improved, and the economical benefit can be increased; and the popularization prospect is wide.