The invention discloses a bidirectional transmission chain. The bidirectional transmission chain comprises a plurality of chain link bodies, each chain link body has four side faces, every two adjacent side faces are perpendicular to each other, and each side face is provided with a tooth groove matched with chain wheel teeth. Two first shaft lugs are arranged on the first end face of each chain link body, and first shaft holes are correspondingly formed in the two first shaft lugs. Two second shaft lugs are arranged on the second end face of each chain link body, second shaft holes are correspondingly formed in the two second shaft lugs, and the axes of the second shaft holes are perpendicular to those of the first shaft holes. The first shaft lugs of one chain link body and second shaft lugs of the other chain link body are sequentially connected through connection blocks, the connection blocks are provided with two rotating shafts of which a certain angle is formed, and the two rotating shafts are rotatably connected with the first shaft holes in one chain link body and two second shaft holes in the other chain link body respectively. The bidirectional transmission chain can bend in two directions at the same time, is simple in structure and has identical transmission performance in the two bending directions. The rotating shafts are balanced in stress and long in service life.