The invention discloses a fusion cage. The fusion cage comprises a frame and a porous structure, an inner space is formed in the frame in a defined mode, and through holes are formed in the side wall, the front wall and the rear wall of the frame; the porous structure is arranged in the inner space and provided with multiple micropore units communicated with the through holes, and the micropore units are combined together in a three-dimensional network shape. The strength and rigidity of the fusion cage can be improved by adopting the frame structure; the through holes are formed in the frame, the porous structure is arranged in the frame and comprises multiple micropore units combined in the three-dimensional network shape, the bone induction capacity can be improved substantially, and synosteosis is facilitated.