This work demonstrates a time-optimized hierarchical cascading technique (HCT) for full 3D surface acoustic wave (SAW) device simulations. Firstly, we analyze the multidirectional cascade for full 3D HCT. Then based on the process, it is demonstrated that how the cascading order in X and Y direction influences the time and memory cost of the cascading process. Then the computing time of each step are recorded to verify the analysis. Based on the full 3D simulation, the ‘Y→X cascade’ saves 62.3% time and 30.1% memory than ‘X→Y cascade’ in the cascading process. Finally, the optimized ‘Z → Y → X’ cascading method is proposed, which not only reduces the time and memory cost but also reveals more details of the resonator in the simulation.