A hinge durability testing device for testing the durability of a hinge hinging a cover with a main body, includes a main body holder holding the main body, a cover holder holding the cover, the cover holder hinged to the main body holder, the cover holder comprising two support rods and a connecting rod; each support rod comprising a first surface facing the other support rod, and a second surface adjacent to the first surface; each first surface defining a first sliding groove, and each second surface defining a second sliding groove comminuting with corresponding first sliding groove; two connecting elements, each connecting element located on one end of the connecting rod and slidably mounted in one of the first sliding grooves; a plurality of locking elements, each locking element retained on one of the connecting elements and slidably mounted in one of the second sliding grooves.