This paper presents an analytical sub-domain model for predicting magnetic flux density and winding inductance flux switching permanent magnet (FS-PM) under armature reaction. It is obtained by solving Poisson and Laplace equations in polar coordinates for each domain, i.e. air gap, rotor and stator slots. The model accounts for the influence of interaction between the stator slots and air gap, as well as rotor slots and air gap and winding inductances are obtained from the analytical method and compared by finite element analysis (FEA). Magnetic field distribution are derived from the analytical method and verified by finite element analysis (FEA).