The optimized design of foam aluminum foam muffler is carried out based on optimization software ISIGHT. The muffler performances before and after optimization of parameters, such as the length and diameter of inlet pipe, outlet pipe and idle pipe were simulated and analyzed with software FLUENT and SYSNOISE. The results show that sound transmission loss after optimization increases in average by about 5 dB, and pressure loss reduces by about 11 % comparing with that before. Consequently, the optimized foam aluminum muffler is of better acoustic and aerodynamic performance.