In this paper, the flux-regulation capability of a 12-stator-slot/10-rotor-pole hybrid excitation flux-switching (HEFS) machine with three types of magnet materials, namely Ferrite, SmCo and NdFeB, are evaluated based on finite element analysis. Due to the unique constrained dimensions between the magnets and field windings slots as well as the saturation effect, reasonable matches between the magnets dimensions and field slot area are investigated, which supply a reference for the design of the relative new HEFS machine adopting different materials. The predicted results indicate that for Ferrite, an excellent flux-regulation capability can be achieved and the airgap flux-density can be modulated in a wide range, while in the cases of SmCo and NdFeB, the regulation ranges are limited with the current field-winding topology and the configurations for the magnets and field windings are restricted.