Abstract: An ecological restoration method for seawater back-flowing farmlands in a tropical region includes the following steps: performing soil ridging on a seawater back-flowing saline-alkalized land by using a whole-mulching double-ridge model thereof, a ridge body that has been ridged is a trapezoidal structure, and perpendicular to a direction of a coastline; planting a salt-tolerant plant on ridges, and planting Acanthus ilicifolius in furrows. Salts on the ridges are rinsed into the furrows by means of natural precipitation and irrigation; the Acanthus ilicifolius that have been planted in the furrows excretes redundant salts by using salt glands; the salt-tolerant plant and the Acanthus ilicifolius are harvested to effectively remove salts, thereby achieving an effect of reducing salts in soil by a dual-function of the ridges and the furrows.