A radial active magnetic bearing (RAMB) was used to present the influence of changing the time and space parameters of the magnetic field on eddy current effect, and the mathematic 2-D model was given. The relationship between power loss and current frequency, rotate speed of the rotor has been analyzed by finite element method, especially that of changing both of the two parameters. Finally, the numerical result showed that, the square of power loss arising from the change of two parameters equaled to the sum of the two separate squares, which could be used to calculate the power loss step by step.