Abstract: A series of volcanic rocks occur between the depth of 335 m and 2050 m with a thickness of 1750 meters in the Well J1 of Liaohe Oilfield,but it is not found in other wells of the oilfield.The age of the volcanic rocks and their contrast to those in the other wells are the key to analysis on the tectonic evolution of this area.By analysis of the isotopes of the volcanic rocks,combining with other correlative data,the age of the volcanic rocks in Well J1 is determined.Thus,the strata sequence of the area is established.Based on the results of tectonic evolution analysis,the distribution of favorable petroleum areas is predicted,which is the proof for petroleum exploration.