By analyzing the radioactive isotope（Th and U）abundances of the mafic and ultramafic rocks，this paper estimates the quantity of heat of the mantle、 corona and tail of the mantle plume in Emei igneous province，and expounds and further proves the existence of thermal anomaly with distinct thermal gradient in the mantle o f the Emei igneous province. Finally the paper discusses the characteristics of the thermal origin、the formation and development of the Emei mantle plume.