DC-biased magnetic induction can occur in homopolar inductor alternator (HIA). In this paper, an experimental method is introduced and the corresponding experimental platform is constructed to measure the magnetic loss characteristics of magnetic material under DC-biased magnetic induction. The curves of the magnetic loss under DC-biased magnetic induction are obtained. The magnetic loss of HIA under DC-biased magnetic induction is calculated. The influence of the structure parameter and excitation current on the stator core loss is investigated. Some significant conclusions include: the magnetic material suffers an increase in magnetic loss under DC-biased magnetic induction relative to sinusoidal induction; the magnetic loss of HIA, which is quite different from the loss of conventional electrical machine under sinusoidal induction, is almost proportional to the operating speed; the stator core loss of HIA achieves to the maximum value when the coefficient of the rotor tooth width is approximate to 0.5.