The thermal connection and electrical connection of two thermoelectric modules are analyzed when Thomson effect is taken into consideration.The discussion is focused on the refrigerating capacity and coefficient of performance of the four connection patterns，to analyze the contribution of following factors to the performance of thermoelectric refrigeration system，i.e.，the number of thermocouples ratio，operating current，and the ratio of the cross-sectional area to the length of thermoelectric element.It was found that the thermal parallel and electrical series mode could be chosen at the high cooling load or low temperature difference requirement.At the high temperature difference requirement

the thermal series mode could be chosen，and the cooling capacity of thermal series and electrical series mode is always larger than thermal series and electrical parallel mode.However，at the middle temperature difference requirement

the thermal parallel and electrical series mode could be chosen at the large cooling load requirement，and the thermal series and electrical series mode could be chosen at the high coefficient of performance (COP)requirement.The optimum working conditions and range of application obtained for the four connection patterns will be a theoretical support for selection and optimization of the connection strategy for thermoelectric refrigeration modules in practical applications.