This　paper　proposes　two　axial-flux　permanent　magnet　(AFPM)　machines,　i.e.,　NS　and　NN　type,　which　all　have　the　same　stator　and　rotor　structures　but　the　different　magnetic　circuits.　Since　both　PM　magnetomotive　force　(MMF)　and　armature　reaction　MMF　of　the　proposed　AFPM　machines　are　modulated　by　H-type　armature　stator,　more　field　harmonics　that　contribute　to　electromagnetic　torque　will　be　generated.　The　electromagnetic　torque　generation　mechanism　of　the　proposed　AFPM　machines　is　revealed　and　investigated　from　the　perspective　of　air-gap　field　modulation.　The　MMF-permeance　model　is　established　to　analyze　the　field　modulation　process　of　the　PM　MMF　and　armature　reaction　MMF.　Based　on　the　effective　air-gap　field　harmonics　that　generating　steady　electromagnetic　torque,　the　electromagnetic　torque　generation　mechanism　of　the　proposed　AFPM　machines　can　be　confirmed.　A　finite　element-based　harmonic　restoration　method　is　used　to　quantify　the　electromagnetic　torque　generation　mechanisms　of　the　proposed　AFPM　machines.　It　shows　that　the　total　electromagnetic　torque　of　the　AFPM　(NN)　machine　is　lower　than　that　of　the　AFPM　(NS)　machine,　while　the　AFPM　(NN)　machine　has　higher　field　modulation　electromagnetic　torque　component　due　to　the　more　significant　field　modulation　effect.