Abstract: The existing project operation data shows that the dynamic characteristics of grid-connected converters (GCC) are closely related to the operating points. Due to the influence of external factors such as new energy output fluctuation and load throwing, the operating points of the converter show random time-varying characteristics. Therefore, it is important to analyze the system stability at all operating points in the whole operating interval. Conventional impedance/conductance analysis method can effectively analyze the stability of GCCs when they operate at specific operating points, but when all possible operating points of the system are considered, the analysis needs to be repeated several times, which is a large and difficult task. To solve this challenge, a multivariate modeling approach considering the operating points variables is proposed. The operating points variables are introduced into the conductance model, and the multivariate single input single output (SISO) model of the GCC is established through the control loop reconstruction. The proposed model directly includes the operating points variables, and thus can effectively analyze the dynamic characteristics of the converter in the full operating interval. In addition, a stability analysis method based on the safe operation region is proposed to realize the intuitive characterization of the system stability in the multidimensional operating interval by considering the maximum transmission limit and dynamic characteristics of the converter. Simulations and experiments validate the correctness of the proposed multivariate SISO model and the analysis method based on the safe operation region. The proposed method has wide application potential in engineering scenarios such as analyzing the operation limits of power electronic equipment, guiding converter design and assisting power devices to play the extreme performance.