Disclosed are a reliability test fixture and an online test device (100) for a flexible display component. The fixture comprises a support (110) and a rotating shaft (120) rotatably mounted on the support. A engagement recess (122) for fixing a flexible display component is provided in an axial direction on the surface of the rotating shaft (120). A test module (130) used to detect an electrical parameter of an internal circuit of the flexible display component is disposed inside the rotating shaft (120). The test module (130) has a test contact (132) for electrically connecting to the flexible display component. During a test, the flexible display component is fixed in the engagement recess (122) and is electrically connected to the test module (130). In this way, each time the rotating shaft (120) bents the flexible display component, the test module (130) can timely detect the electrical parameter of the internal circuit of the bent flexible display component. The reliability test fixture and online device can form an online reliability test device of a flexible display component, so as to test in real time the change of the internal circuit of the flexible display component.