Thermoelectric technology, widely applied to military, aerospace, medicine and microelectronics transforms thermal energy to electricity by the use of thermoelectric materials. In recent years, as the problem of energy and environment looms large, thermoelectric technology is gaining more and more attention. This paper introduces basic principles of thermoelectric technology, summarizes the latest advancement of thermoelectric materials, illustrates the structure of thermoelectric generator and way of heat radiation and discusses current problems of thermoelectric power generation technology as well as methods to improve its generation efficiency