Abstract: Anda Sag is adjacent to Sanzhao Sag in the northern Songliao Basin and has good petroleum geological conditions for generating petroleum. The shallow-middle layers in Anda Sag have displayed good oil and gas exploration potential in the recent years. But it is still a puzzle about the unclear oil source, which restricts the exploration in this area. The structural evolution relations of Anda Sag with the surrounding structural belts, such as Sanzhao Sag in the south of Anda Sag, Heiyupao Sag in the north, Daqing placanticline in the west and Mingshui terrace in the east, were studied using the balanced section. The assay data and geochemistry indicator show that Anda syncline is an isolated sag and possesses the conditions for forming the isolated hydrocarbon-generation kitchen. According to the oil-source correlation, the structural belts in the west and north parts of Anda Sag have great exploration potential and the further exploration object should be focused on the fault-lithologic reservoirs.