The gear ratio variable topology of a magnetic gear with an integrated harmonic modulator is analyzed using a magnetic permeance model. A dynamic characteristic equation is derived in consideration of the gear ratio between each layer constituting the magnetic gear: the driving side, the driven side, and the control side layer. Based on derived transfer function, the frequency characteristic between driving torque and angular speed of the driving side is analyzed. Theoretic model is compared with an experimental test result using the in-house dynamometer. In the general magnetic gears, the gear ratio is variable so that speed between each layer decelerates with gear ratio, but transmission torque is constant regardless of gear ratio. In this study, these characteristics are also verified through theoretical methods and experimental results, respectively.