The invention discloses an automatic detection mechanism for appearance integrity of a ball bed high-temperature reactor fuel element, belonging to the field of reactor engineering equipment. The automatic detection mechanism comprises a rack, a detection module, a clamp module, a clamping rotation module and an element guide rail module. The automatic detection mechanism can realize the accuratepositioning of a novel fuel element, the effective clamping and the sufficient rotation, and finishes twice automatic detection processes of the element, thus being applied to detect the appearance integrity of the automatic detection mechanism.