With the increasing adoption of electric vehicles (EVs), Active Sound Design (ASD) has become a crucial method for enhancing both sound quality and the overall driving experience, addressing the absence of the distinctive engine sounds found in internal combustion vehicles. This paper presents an ASD offline simulation software developed on the MATLAB platform. The software integrates a vehicle dynamics model with three key sound synthesis algorithms—order synthesis, pitch shifting, and granular synthesis—enabling comprehensive control strategy development, real-time sound playback, and rapid adjustments. It comprises multiple functional modules, including configuration, order generation, pitch shifting, and granular synthesis interfaces, offering a user-friendly environment for flexible sound parameter tuning under various simulated driving conditions. Users can easily configure vehicle dynamics, adjust gain values, and visually manipulate sound parameters to create a customized ASD experience. Real-world vehicle testing validated the strong alignment between the simulation results and actual in-vehicle performance, confirming the effectiveness and responsiveness of the synthesized ASD sounds. Additionally, the offline simulation software significantly improves development efficiency, facilitating faster deployment compared to existing commercial software solutions.