Abstract: In response to the high requirements for practicality and accuracy in existing decomposition and identification methods for broadband multi-state signals in distribution networks, this paper proposes an active distribution network broadband multi-state signal decomposition and identification method based on infinite impulse response-Taylor Fourier transform (IIR-TFT). First, the voltage/current signals of the power grid are obtained through preprocessing. Second, the IIR algorithm is employed to decompose harmonic/inter-harmonic components. Then, the TFT algorithm is utilized to dynamically identify the parameters of harmonic/inter-harmonic components, yielding the parameters of each harmonic/inter-harmonic component. Finally, parameter compensation is performed to obtain the decomposed and identified harmonic/inter-harmonic component signals. The accuracy of the IIR-TFT algorithm has been verified through simulation experiments with constructed signals and measured signals from the NI USB-6229 acquisition system, demonstrating a relative error within 3%. This confirms that the proposed method is an accurate and effective approach for the decomposition and identification of broadband multi-state signals in distribution networks.