Under high-frequency operating conditions, variable-frequency converters constructed with Gallium Nitride (GaN) switching devices are susceptible to issues such as voltage oscillations and crosstalk, leading to electromagnetic interference (EMI) hazards. Among these factors, parasitic parameters significantly influence the operational characteristics of GaN switching devices. Butprecise analysis of these parameters typically requires expensive high-performance testing equipment. Based on netlist files, this study aims to address this challenge by importing the Spice models provided by device manufacturers into Simulink, the co-simulation technology of which, together with a Graphical User Interface (GUI), enables data acquisition to achieve simulation results approximating actual measurements. Experimental validation confirms the feasibility of the proposed method. Built upon this foundation, a voltage oscillation prediction and analysis software tool was designed, which significantly enhances research and development efficiency while reducing research and development costs.