The invention discloses a flexible self-locking structure tool for testing an axial magnetic suspension stator element. The flexible self-locking structure tool comprises a universal joint core; two installation holes whose axes are not intersected but are perpendicular to each other in space are formed in the universal joint core; a first mandrel and a second mandrel are fixed in the installationholes respectively; a stator tool is movably arranged on the first mandrel; and a rotary joint is movably arranged on the second mandrel. After magnetic core contact between a stator element and a rotor element, the stator tool is rotated and the pressure from the tool is applied to the stator tool; the universal joint core rotates on the rotary joint through the second mandrel; and the stator tool rotates at the universal joint core through the first mandrel, so that magnetic core contact between the stator element and the rotor element is realized. Self-locking of the stator tool is realized based on the friction force by an expansion pipe, a screw, the rotary joint and the universal joint core and fixation without any offset is realized, so that the follow-up testing becomes convenient.