In 2002- 2003, the First Inner Mongolian Archaeological Team, IA, CASS, carried out two seasons of excavation on the Xinglonggou site. The work resulted in the confirmation of the first locality as a large-sized settlement of the middle Xinglongwa culture (8000-7500 BP). The significant findings in dwelling form, settlement layout, burial custom, primitive religion, economic formation and environmental archaeology represent a new type in the Xinglongwa culture. The second locality is left over from a small-sized ditch-surrounded settlement of the Hongshan culture (5500-5000 BP). Its discovery made up the gap of late Hongshan Culture sites in the prehistoric data. The third locality remains of a small-sized ditch-surrounded settlement of the Lower Xiajiadian culture (4000-3500BP), which offers new material for studying the civilizing course and early state form of the West Liaohe River valley. The excavation of the Xinglonggou site will forcefully promote the deep-going study of prehistoric archaeological cultures in Northeast China and exert active influence upon the research on Sino-Japanese cultural relations in prehistoric times.