In view of accurate and fast design of ladder surface acoustic wave(SAW) filter with arbitrary and complex topology, based on acoustic/electrical/magnetic multi-physical field coupling full-wave simulation platform and combined with genetic optimization algorithm and general graphics processor(GPGPU) acceleration technology, the hierarchical cascade exact model(HCT) is used to replace COM model for the design and optimization of SAW filter. The calculation and optimization speed are comparable with that of COM model. The optimized design and development of 42°Y-X LiTaO3 conventional SAW filter with insertion loss of 0.67 dB and 2 dB fractional bandwidth of 3.85% verifies the effectiveness and feasibility the proposed method.