The present invention relates to heart septal defect occlusion devices with adjustable length tether which can adapt the interseptal length of the device to the unique anatomy of the patient. The right disc as recited in the present invention is made from a double-deck metal mesh with contraction function, and the left disc is made from at least two skeletons covered by membranes. The two discs are active linked together. Because the connection of the two discs has gimbal function and the distance between the two discs may expand and contract suitably, the device can adapt to the unique anatomy of the patient. Therefore the two discs may attach to the heart valves closely and increase its closing ability. Furthermore it can reduce the thrombus and operate more easily.