An acoustic emission test sensor fixing device, comprising a radial positioning mechanism, supporting mechanisms, bases, acoustic emission test sensor mounting mechanisms, and parallelism adjusting members, wherein the supporting mechanism comprises a main supporting arm and an auxiliary supporting arm, with one end of the auxiliary supporting arm is fixedly connected to or hinged with the main supporting arm and the other end is provided with kink shaft members which are symmetrical about the auxiliary supporting arm; and the bases are provided with plugholes which form revolute pairs with the auxiliary supporting arm. The above components are assembled as follows: the main supporting arms of the two sets of supporting mechanisms are connected to the two free ends of the radial positioning mechanism respectively in the way that the auxiliary supporting arms of the two sets of supporting mechanisms are located at the inner sides of the main supporting arms respectively and are arranged axis symmetrically with respect to the central line of the radial positioning mechanism, and the kink shaft members of the two auxiliary supporting arms are respectively inserted into the plugholes of the two bases to form revolute pairs, the two sets of acoustic emission test sensor mounting mechanisms are respectively mounted at the two bases, and the two sets of parallelism adjusting members are respectively mounted on the two main supporting arms and correspond to the positions of the bases.