The invention discloses a fusion cage which is of a loose solid structure composed of a stereoscopic net structure. The stereoscopic net structure forms a plurality of net holes in the interior and the surface of the fusion cage. The loose solid structure in a stereoscopic net shape is adopted in the fusion cage, the fusion cage does not need to be made into a hollow cavity form, and therefore the fusion cage has enough rigidity and supporting face to support the intervertebral stress of the human body. Due to the fact that the supporting face of the fusion cage is large, the complication of collapse is avoided. Meanwhile, the solid fusion cage in the stereoscopic net shape does not need filling materials, the defect that an existing fusion cage needs to be filled with autologous tissues is overcome, the situation that new trauma is caused by acquiring the autologous tissues is avoided, the operation time consumed by an operator for setting autologous tissues is saved, and patients with poor skeletal structures cannot be limited.