Igneous rocks in Chagan sag of Yin'gen basin were studied to understand their lithofacies and seismic recognition marks. Different types of igneous lithofacies were identified, with overflow facies being the most common. Seismic recognition marks were established based on characteristics like high seismic wave velocity and density. It was found that deep faults control the distribution of igneous rocks and traps, with favorable zones for igneous reservoir prospecting near fault-developed belts.