Abstract: A heat flow plot from 117 measurements on both sides of the Tancheng-Lujiang Fault Zone shows a larger frequency of heat flows between 50 mW/m² and 80mW/m² in the central south segment of the fault with an average of 67.67mW/m²,notably higher than the average global value(63mW/m²),also somewhat higher than that of the China Continent (66mW/m²).There is a gradient zone from the west to the east side of the fault zone,rising from an average of 55.35mW/m² on the west side to an average of 67.78mW/m² on the east side.This suggests there may be remarkable difference in the crustal structure of both sides of the fault,as is agreeable to the existence of a low velocity,low resistance layer in the lower crust and a higher Moho on the east side of the fault revealed by geophysical survey.