When the distorted flux is induced in a magnetic circuit, the minor loops arise sometimes inside the major hysteresis loop. The area, accordingly the hysteresis loss of the minor loop,is affected by its amplitude and position, by the maximum flux density, by the quality of material, etc.. In this paper, we describe the experimental studies of the factors on the minor loop hysteresis loss. A method of getting the displacement factor of a minor loop which is placed at arbitrary position and has any amplitude is developed from our experimental results. Using this method, the core losses caused by the distorted flux can be calcuLated within the error less than three percent, even if the amplitude of the minor loop becomes near to the amplitude of the major loop.