The invention relates to an artificial gulfweed field and a building method thereof. The artificial gulfweed field is formed by hard adhering substratums, the two ends of each hard adhering substratum are provided with holes used for fixing, and gulfweed seedling ropes are wound on the hard adhering substratums and fixedly tied up through tying straps; the position of the artificial gulfweed field is selected between a neap tide low water line and a spring tide low water line of a hard substrate intertidal zone, holes are formed in ledges at the position, the hard adhering substratums are fixed to the holes through expansion screws, quick-freezing cement is poured on the expansion screws, gaps are reserved between the opposite faces of the gulfweed hard adhering substratums and the ledges, and gulfweed seedlings in the gaps can make contact with sea water and air fully. The artificial gulfweed field is large in popularization range and low in cost; the fixation and growth conditions of gulfweed in the artificial gulfweed field are good, and the labor intensity of cultivation work and follow-up assessment work is low; the gulfweed hard adhering substratums are moderate in weight and flexible to operate, and the gulfweed is high in survival rate, high in fixation force and easy to detect and manage.