As the world's environment and the increasingly serious energy crisis,green environmental protection of the thermoelectric material was attached great importance to by people,has caused the extensive ...This paper summarizes the definition and development history of thermoelectric materials; Summarizes the research and development progress of thermoelectric materials; The author introduces the application of thermoelectric materials, classification, and thermoelectric effect; Summarizes the ways to improve the performance of thermoelectric material properties,; Thermoelectric materials are introduced in the temperature difference power generation and the thermoelectric refrigeration applications; And the Ca3Co4O9, elaborates the structure and properties of the Sr.Study of the Ca3Co4O9 Sr doped by chemical coprecipitation method, specific steps are: raw material of the confecting of computing - raw material weighing -, aging, washing, drying, grinding, calcination, milling, pressing, sintering. Finally the Ca3Co4O9 doped Sr thermoelectric materials XRD detection and surface microscopic morphology analysis