Aiming at the severe waveform distortion of output vibration signal caused by nonlinear parameters of the long-stroke lowfrequency electromagnetic vibrator, the preliminary harmonic compensation control was carried out based on analysis of electromechanical coupling model and equivalent transfer function. By calculating the first and second-order approximate vibration displacement solutions of the electromechanical coupling equation that characterize the nonlinear characteristics of the vibrator, the accurate harmonic compensation control quantities that need to be superimposed on the input signal was analyzed, and then the high-precision compensation control of the output signal waveform distortion was obtained. The simulation analysis and experimental test results show that the control method based on transfer functions and approximate solutions could effectively compensate the output signal harmonics in the entire frequency range. Typically, the acceleration distortion corresponding to 0. 1 Hz was reduced from 22. 81% to 4. 5% by transfer function control, and further reduced to 4. 42% and 1. 78% by the first and second-order approximate solution control, respectively. The results show that the second-order approximate solution method exhibits higher harmonic control accuracy. Keywords:low-frequency electromagnetic vibrator; harmonic control; electromechanical couplin