Abstract: Changling rift in Songliao Basin was transformed in a number of periods.As a result, the present-day remaining basin is significantly different from basin prototype, affecting further oil and gas exploration of Huoshiling formation. Based on the study of the remaining basin characteristics and the geological background and data of this region as well as taking into account the applicable scopes of various methods and influencing factors, the vitrinite reflectance method and the profile trend method are selected to calculate the denudation quantity of Huoshiling formation in the light of different wells and areas. Restoration of the basin prototype of that period in the research area indicated that it was obviously a half-graben and horst structure, clarifying the location and scale of the depression during the basin prototype period. Based on analysis of the geological conditions for accumulations, it is pointed out that the stratigraphic onlap zone of Huoshiling formation on the western slope and the high position (volcanic rock body) of structure in the remaining dustpan-like sag of the western and southern fault zone are the favorable targets for oil and gas exploration in this region