Abstract: Thermoelectric generator (TEG) which is driven by natural gas can supply direct current to CP system of gas transmission pipeline in remote and no power supply district.TEG is a new type of power source which can compete with the solar energy battery.Its property is safe, reliabale and unmanned maintenance.The supply range is 30~3000 W.At present, TEG is widely used all over the world.TEG works by thermocouple with aluminium cooling fan to cool the thermocouple, therefore, TEG's power is influenced by environmental temperature.The difference between the design of CP power source with the TEG and the other CP power source is that: ① TEG's power is variable with the local environmental temperature, and based on annual higher operating temperature in the design, ② maximum power of TEG should be an ideal value, otherwise the number of TEG had to be increased or installed transformer, ③ the number and location of TEG should not be limited, proper groundbed location may be more important.What more the paper introduced includes the work principle of TEG, electrical property, design steps, application and economical and technical comparison between TEG and the other power source.