A spinal rod, comprising: a rod assembly comprising a movable rod, a stationary rod and a cap, wherein the movable rod is on an upper side of the spinal rod and further comprises a second connecting portion and a second rod portion on the upper side of the second connecting portion, a diameter of the second connecting portion is larger than a diameter of the second rod portion, the stationary rod is on a lower side of the spinal rod and further comprises a first connecting portion and a first rod portion on the lower side of the first connecting portion, a diameter of the first connecting portion is larger than a diameter of the first rod portion, and the cap is between the stationary rod and the movable rod for fixing the movable rod and the stationary rod; and an elastic assembly comprising a first elastic element and a second elastic element, wherein the elastic assembly is accommodated by the rod assembly, the first elastic element is between the cap and the stationary rod, a compression of the first elastic element by the movable rod shortens an overall length of the rod assembly, and the second elastic element provides a flexibility for movements of the movable rod and the stationary rod in a frontal plane and a sagittal plane, the spinal rod being characterized in that: the second elastic element is a rod structure partially accommodated by the movable rod and the stationary rod and passes through a center of the first elastic element, an end of the second elastic element is fixed inside the first rod portion, another end of the second elastic element is fixed inside the second rod portion, and the first rod portion, first connecting portion, the second rod portion, and the second connecting portion are of hollow structures. a rod assembly comprising a movable rod, a stationary rod and a cap, wherein the movable rod is on an upper side of the spinal rod and further comprises a second connecting portion and a second rod portion on the upper side of the second connecting portion, a diameter of the second connecting portion is larger than a diameter of the second rod portion, the stationary rod is on a lower side of the spinal rod and further comprises a first connecting portion and a first rod portion on the lower side of the first connecting portion, a diameter of the first connecting portion is larger than a diameter of the first rod portion, and the cap is between the stationary rod and the movable rod for fixing the movable rod and the stationary rod; and an elastic assembly comprising a first elastic element and a second elastic element, wherein the elastic assembly is accommodated by the rod assembly, the first elastic element is between the cap and the stationary rod, a compression of the first elastic element by the movable rod shortens an overall length of the rod assembly, and the second elastic element provides a flexibility for movements of the movable rod and the stationary rod in a frontal plane and a sagittal plane, the spinal rod being characterized in that: the second elastic element is a rod structure partially accommodated by the movable rod and the stationary rod and passes through a center of the first elastic element, an end of the second elastic element is fixed inside the first rod portion, another end of the second elastic element is fixed inside the second rod portion, and the first rod portion, first connecting portion, the second rod portion, and the second connecting portion are of hollow structures.