Thermal remote sensing oil-gas exploration is based on the theory on hydrocarbon micro-seepage over oil-gas field. Hydrocarbon moves upward along cracks and fractures in the form of micro-hydrocarbon from oil-gas field and interacts with surrounding material

resulting in round-like hydrocarbon alteration area and a series of indicators on surface and subsurface concerned. Remote sensing data in the range of infra-red band （8—14μm） can be used to attract the information of thermal anomaly because hydrocarbon that reaches the surface and subsurface causes changes of physical and chemical properties of surface material

such as reduction of thermal conductivity and increase of thermal capacity

or production of oxidant heat. The thermal anomaly over oil-gas field caused by hydrocartbon micro-seepage is the most direct and significant criteria for oil-gas remote sensing exploration. It is of great practical and economic significances to identify these criteria and study their temporal effectiveness.It has been revealed by the authors in the former research that Oil-gas Thermal Infra-red Remote Sensing Exploration is more effective in a new site for oil-gas-exploration

where the surface condition of hydrocarbon alteration area is well reserved

than the explored oil-gas field where the surface condition of hydrocarbon alteration area was seriously destroyed.In order to compare the effectiveness of remote sensing data acquired before or at the beginning of and after oil-gas exploration

two sample areas has been chosen over the known oil fields in Erlian Basin of Inner-Mongolia and a set of NOAA data of two dates and of one date

which represent the data respectively taken at the beginning of oil-gas exploration and at the end of the exploration. An integrated analysis has been carried out by overlaying remote sensing data in the studied areas with data of geo-chemical exploration. It was shown that the use of remote sensing data taken before or at the beginning of oil-gas exploration

integrated with other information sources

could receive best economic benefit when thermal infra-red remote sensing is used for oil-gas exploration. This is applicable for not only a new exploration site but also a continuing exploration of the old oil-gas field.