Abstract: The integration of large-scale power electronic devices may cause serious sub/super-synchronous oscillation problems. This type of oscillation belongs to the category of electrical oscillations and has the characteristics of complex oscillation mechanism and wide spreading range. Existing eigenvalue analysis methods require topological analysis of the network to select the independent state variables, and then eliminate algebraic variables to obtain the state matrix of the whole system. This process is difficult to use in the small-signal stability analysis of complex structural systems in actual research. Considering that the state space and eigenvalues of the system have a clear mapping relationship in the continuous-time and discrete-time domain, this paper proposed a discrete-time state space modelling method for the complex renewable AC/DC hybrid system. By modelling the power components as a unified discrete-time state-space model and equivalent discrete-time circuit, and forming the discrete-time circuit network according to the system topology, the node analysis method was used to quickly obtain the state matrix of the whole system. Then the eigenvalues were solved to quantify the oscillation characteristics of the system. The modelling process of this new approach was clear and easy to be realized programmatically. In addition, it also had strong adaptability to network structure changes, and thus was suitable