Abstract: Besides included within carbonate mineral (determined by the acidolysis desorbed hydrocarbon method),hydrocarbons existing in surface medium are also occluded in clay and other silicate mineral.The pyrolysis desorbed hydrocarbon technology introduced in this paper makes this part of hydrocarbons desorbed under low and middle temperature.This method is fast and economical,and has brought about satisfactory results for geochemical exploration when applied in the loesslands of North Shaanxi province,the acid soil areas of Henan province and other special geologic landscape areas.It is a new technology worth spreading in gas and oil exploration.