Abstract: The discovery of hydrocarbon in Yixian Formation of Xiushui Basin has made Yixian the target formation for oil-gas survey in northwestern Liaoning Province. Based on the technical methods of drilling core cataloging, field geological survey and organic geochemical test analysis, using electrical exploration data, 2D seismic and drilling data, the authors analyzed the stratigraphic characteristics, hydrocarbon generation conditions, basin formation and evolution history of Lower Cretaceous in Xiushui Basin. The results show that the No.3 mudstone source rock of Yixian Formation has a wide distribution range, a large sedimentary thickness, and suitable organic matter abundance, type and maturity, which means the mudstone has good hydrocarbon bearing conditions and belongs to medium to good source rock. It is considered that Xiushui Basin has undergone four phases of tectonic evolution in Early Cretaceous, and has the source-reservoir-cap rock assemblages and the prospective area for petroleum exploration. The above research is expected to provide support for further exploration of oil and gas resources in this area.