Abstract: The impedance model of the offshore wind power via high voltage direct current (HVDC) connected-grid systems is the basis of its stability analysis. However, existing impedance modeling methods ignore the coupling between the wind farm and the modular multilevel converter (MMC), which may lead to inaccurate determination of system stability. Therefore, in this paper, equivalent impedance modeling method for MMC-HVDC considering coupling of offshore wind power and MMC impedance is proposed, which considers the impedance coupling of them. First, the unified sequence impedance model of MMC and wind farm is established by using the harmonic state space. On this basis, the coupling mechanism of the AC port voltage, current and impedance of the wind farm and the MMC is analyzed to obtain the equivalent impedance of them. Finally, the impedance coupling of wind farm and MMC is proposed to quantitatively analyze the influence of different control links on the coupling degree of wind farm and MMC. The accuracy of the proposed model and the influence of impedance coupling on system stability are verified by the time-domain simulations in the MATLAB/Simulink. The RT-Lab hardware in the loop experiment proves the validity of the model in the system stability analysis.