Abstract: The incident power and scattered harmonic power relation of nonlinear targets (hereinafter to be referred as harmonic scattering characteristics) demonstrates significant importance in enhancing the robustness of nonlinear detection systems and subsequent target identification and recognition. In this paper, the modeling method of the nonlinear target harmonic scattering characteristics and the corresponding parameter extraction are studied. By establishing an equivalent circuit, this paper derives the relation between the nonlinear volt-ampere characteristic curve and the scattering parameters and proposes a progressive optimization-based solution to improve the efficiency of parameter extraction. Zener diode fundamental wave data is used to illustrate the modeling process, and simulated harmonic scattering characteristics based on the modeled parameters show the consistency with its harmonic measurement. Therefore, the proposed method could be a beneficial reference for obtaining harmonic scattering characteristics of other nonlinear elements (such as PIN tubes, triodes, etc.).