Tip leakage flow (TLF) patterns, which affect compressor performance, are closely related to compressor stability. To date, minimal attention has been given to circumferential non-uniformity of the TLF in a centrifugal compressor with a non-axisymmetric volute structure. In this study, the circumferential difference of the TLF in a centrifugal compressor with a volute during the stall process is analyzed. The circumferential non-uniformity of tip leakage vortex (TLV) trajectories, loading distribution near the tip, and distance between the TLV core and the leading edge (LE) of splitter blades were also investigated. It is show that in the circumferential direction, there are two peaks associated with the angle (a) between the TLV trajectory of the seven main blades and the axial direction. As the stall process progresses, blade 2 loses its work capacity first and the a difference between this blade and the other blades increases. In addition, the tip loading and TLF velocity of blade 2 are at a minimum, and the flow loss in the tip clearance is higher. There is a phenomenon of the TLV breakdown. When the blade trailing edge (TE) is located in the low static pressure region, TLV streamlines appear as a significant turn at the breakdown point. However, the TLV streamlines at other circumferential positions of the impeller outlet do not exhibit this phenomenon.