An intervertebral cage, an implanting apparatus and an operating method thereof are provided. The intervertebral cage for being implanted between two adjacent vertebral bodies includes a body and a connecting portion. The body has a lateral convex surface, an inclined surface, a lateral concave surface and a connecting surface connected sequentially. The connecting portion includes a main portion and a protrusion. The main portion connected to the connecting surface has a through hole. The protrusion is protruded from the main portion into the through hole to form first and second inner arc surfaces. The maximum width of the intervertebral cage is a distance between first and second lines. The first and second lines are substantially parallel to a tangent line of the lateral convex surface and the first line, respectively. The distance between the inclined surface and the first line decreases gradually along a direction away from the connecting portion.