Abstract: This paper comparative studies the influence of unequal inner and outer stator pole number combinations(N_is≠N_os) on the electromagnetic performance of partitioned stator biased flux permanent magnet（PM） machines（PS-BFPMMs）. The polarity of coil flux-linkage is unipolar in PS-BFPMMs with N_is=N_os/2（less PMs） while it is bipolar in PS-BFPMMs with N_is=2 N_os（less slots）. However, the symmetrical bipolar phase flux-linkages can be obtained in both PS-BFPMM with N_is=N_os/2 and N_is=2 N_os when the ratio of Min(N_os, N_is) to the greatest common divisor of Min(N_os, N_is) and N_r（number of rotor pole） is even. Compared with PS-BFPMMs with N_is=N_os under the individual optimal rotor pole numbers and the same rated copper loss, PS-BFPMM with N_is=N_os/2 exhibits 41% lower phase back-EMF, 38.4% smaller average torque and 1.1% lower PM utilization efficiency while PS-BFPMM with N_is=2 N_os has 20.4% higher phase back-EMF, 30.3% larger average torque and 24.4% higher PM utilization efficiency. Moreover, the reluctance torques are negligible in both PS-BFPMMs with N_is=N_os/2 and N_is=2 N_os due to the extremely low saliency ratios. The analyses have been experimentally validated by several prototype machines.