Abstract: On the basis of the analysis of structural geology,petroleum geology and tectonic stress field at Fangsheng 9 drill area of north Songliao basin,three-dimensional tectonic stress fields at the end of Nunjiang Formation of Early Cretaceous,the end of Mingshui Formation of Late Cretaceous and present are simulated respectively,and then we discuss their application to fissure predication.The results have a good agreement to the comprehensive conclusions from structural geology and petroleum geology,and will play a role in hydrocarbon exploration and development in the research region.