[Objective] To address the demands of low-altitude heavy-duty unmanned aerial vehicle propulsion systems for high power density and robust anti-saturation capability, this study designs an axial flux permanent magnet machine (AFPMM) with a soft magnetic composite (SMC) stator core. The research aims to reveal the influence of stator material properties on machine inductance characteristics and provide theoretical support for enhancing the electromagnetic performance of AFPMM. [Methods] Firstly, a three-dimensional electromagnetic field model of AFPMM was established based on the finite element method. Then, the magnetic circuit characteristics of stators made of SMC, grain-oriented (GO) silicon steel, and non-oriented (NO) silicon steel were comparatively analyzed. Finally, the nonlinear variation rules of dq-axis inductances with current angle and current amplitude were quantified, and the saturation mechanisms of machine inductance under different stator materials were systematically investigated through magnetic flux density distribution analysis. [Results] The results showed that the machine with SMC stator has isotropic properties and optimal anti-saturation capability. The machine with GO silicon steel stator has anisotropic characteristics with the highest initial inductance as well as output torque, but the inductance drop was significant at high currents. The inductance characteristics of machine with NO silicon steel stator was between SMC stator and GO silicon steel stator. [Conclusion] Although the machine with GO steel stator offers higher torque density, its performance necessitates optimized magnetic circuit design to suppress cross-saturation effects. The machine with SMC stator can effectively balance the dq-axis inductance and alleviate local saturation, which is suitable for high-frequency and complex magnetic circuit working scenarios. This study verifies the advantages of SMC stator in meeting the practical demands of unmanned aerial vehicles and provides theoretical guidance for material selection and electromagnetic design in high-performance motor.