Abstract: To analyze the impact mechanism of single harmonic wind speed on self-excited forces of a typical cross-section, a thin flat plate was taken as the research object. The self-excited forces of the thin flat plate under the single harmonic wind speed were calculated using the forced vibration method. Additionally, a self-excited force correction model for the thin flat plate under the single harmonic wind speed was established based on the principle of amplitude modulation. On this basis, by identifying the flutter derivatives of the thin flat plate under different single harmonic wind speeds, the applicability of the self-excited force correction model and the strategy for determining the flutter derivative values was tested using both the forced vibration method and free vibration method. The research results show that under the single harmonic wind speed, the amplitudes of the self-excited forces of the thin plate exhibit time-varying characteristics. The phenomenon of cross-superposition and cross-difference frequencies observed in the self-excited force spectrum is successfully explained by the proposed self-excited force correction model. The calculated self-excited forces based on the self-excited force correction model and its flutter derivative values are in good agreement with the simulated values both in terms of time and frequency. The aerodynamic damping terms, the absolute values of \textA_\text2^\mathrm* and \textH_\text2^\mathrm* , both increase with the amplitude of the single harmonic fluctuating wind speed increases, while the aerodynamic stiffness term, \textH_\text4^\mathrm* , decreases as the amplitude of the single harmonic fluctuating wind speed increases. In the free vibration of the thin flat plate, the self-excited force calculated using the correction model still shows high accuracy, further confirming the accuracy and reliability of the proposed self-excited force correction model and the strategy for determining the flutter derivatives.