This　paper　presents　the　common　methods　and　corresponding　drawbacks　concerning　nonlinear　analysis　of　fluxgate　excitation　circuits　and　emphasizes　the　importance　of　nonlinear　analysis　for　these　circuits.　With　regard　to　the　nonlinearity　of　the　excitation　circuit,　this　paper　proposes　the　use　of　the　core-measured　hysteresis　curve　for　mathematical　analysis　and　the　use　of　a　nonlinear　model　that　considers　the　coupling　effect　of　the　core　and　winding　and　influence　of　the　historical　magnetic　field　on　the　core　for　simulation　analysis.　The　feasibility　of　mathematical　calculations　and　simulation　for　the　nonlinear　study　of　fluxgate　excitation　circuit　is　verified　via　experiments.　The　results　demonstrate　that,　in　this　regard,　the　simulation　is　four　times　better　than　a　mathematical　calculation.　The　simulation　and　experimental　results　of　the　excitation　current　and　voltage　waveforms　under　different　excitation　circuit　parameters　and　structures　are　essentially　consistent,　with　a　difference　in　current　of　no　more　than　1　mA,　thereby　verifying　the　effectiveness　of　the　nonlinear　excitation　analysis　method.