[Objective] With the development of electric vehicles, the VIENNA rectifier, as a key component of new energy vehicle charging stations, has also been widely applied. However, when connected to the grid, the VIENNA rectifier injects harmonics into the grid. To address the unclear mechanism of harmonic coupling between its AC and DC sides, this paper establishes a harmonic state space (HSS) model of the VIENNA rectifier. [Methods] Firstly, based on the HSS theory, the VIENNA rectifier was modelled, and the harmonic coupling impedance matrix was derived. Secondly, based on the coupling impedance distribution diagram and the coupling impedance amplitude diagram, the harmonic coupling and transmission relationships between different variables were visualized. Finally, simulations were conducted based on Matlab/Simulink to compare the computational results of the HSS model with the simulation results of the Simulink model, thereby validating the accuracy of the HSS model. [Results] The harmonic coupling and transmission characteristics of the VIENNA rectifier exhibited a cross-frequency transmission relationship whereby the kth harmonic in the AC-side voltage coupled out the k±2th harmonics in the AC-side input current, and the k±1th harmonic in the DC-side voltage. A 10V/6th harmonic disturbance was injected into both the HSS model and the Simulink simulation model, the results indicated that all key variables were affected. However, the small-signal waveforms of these key variables in both models were largely consistent, with minimal discrepancies. This validated the accuracy of the HSS model established in this paper. [Conclusion] The model established in this paper can accurately reflect the harmonic coupling and transmission laws between the AC and DC sides of the VIENNA rectifier, providing a theoretical basis for the parameter design of the converter and the formulation of effective measures to suppress frequency coupling phenomena.