Abstract: Several 6061 aluminum alloy wheel hubs manufactured by forging and spinning process exhibited air leakage during radial testing. Fluorescence detection confirmed that the air leakage of the wheel hubs was caused by rim cracking, and the hubs cracked at the same position. The mechanical properties, chemical composition, macroscopic and microscopic morphology of the fracture surface, microstructure, and micro area composition of a failed wheel hub were analyzed with a material tensile testing machine, a spectrometer, an ultra-depth-field stereomicroscope, a metallographic microscope, and a scanning electron microscope, to determine the cracking mode and cause of the wheel hubs, and corresponding improvement measures were proposed. The results indicate that the failure mode of the wheel hub is fatigue cracking. The cracking cause is that there is a spinning-microcrack-type defect band at the rim, resulting in the hub’s load-bearing capacity being lower than the design requirements. It is suggested to adjust the rim shape or the spinning process to enhance the spinning formability and avoid the occurrence of spinning microcrack defects, to provide technical support for ensuring the service safety of the wheel hubs.