With great development of thermoelectric exhaust heat recovery technology, more and more attention has been paid to optimization of automotive thermoelectric generators (ATEGs). A lot of work has been done on optimization of flow field and thermal analysis. However, investigation on acoustic optimization is rather limited. In this paper, efforts have been paid to study the acoustic performance of a flat-plate TEG, and the feasibility of integration of automotive exhaust thermoelectric generator with muffler was discussed. The internal configuration of heat exchanger looks like “fishbone”. Four factors have been taken into consideration: the spacing of two fins, angle of the fins, the diameter of inlet and outlet of exchanger; and filling sound absorbing material in heat exchanger chamber. Based on these four factors, acoustic analysis was carried out. LMS Virtual.Lab was used to compute the acoustic performance of exhaust-based heat exchanger, and transmission loss (TL) is regarded as the evaluation index for acoustic performance. GT-Suite simulations were used to obtain the pressure drop of TEGs. Results indicate that changing the spacing of two fins and angle of fins have a negligible effect on improving the overall TL of a heat exchanger, decreasing the diameter of inlet and outlet of heat exchanger and filling up the heat exchanger chamber with sound absorbing material improves overall acoustic performance.