In order to improve the power generation performance of automobile exhaust thermoelectric generator, an intermediate fluid thermoelectric generator system is proposed in this work. In the proposed system, the waste exhaust heat is transferred through boiling and condensation of the intermediate fluid. Consequently, the separation between the exhaust channel and thermoelectric module induces a higher heat flux on the hot side of the module. A mathematical model is also established to analyze the power generation characteristics of the proposed system. Compared with the traditional thermoelectric generator system, for the same heat exchange area on the exhaust side, not only is the peak output power increased by 32.6%, but the optimal thermoelectric module area is also reduced by 73.8%. The generation capacity per unit area is 1162 W/m(2) at peak output power, which is 5.12 times that of the traditional thermoelectric generator system.