Based on single well to seismic facies calibration and seismic inversion, the distribution characteristics of deep source rock are analyzed in the northern part of the Songliao basin. The seismic facies of the deep layers can be divided into four types according to the seismic reflection data and the thickness ratio of effective source rock in single wells. The first seismic facies is the features of volcanic reflection, the second is coal reflection, the third mud reflection, the fourth lacustrin clastic reflection. On the basis of the seismic facies analysis, the distribution of the effective source rock in the deep layers is forecast. The distribution characteristics of the effective source rock are controlled by the developing scale of deep fault depressions, and they are various in different fault depressions. The source rock in K1 shis the main effective source rocks and is distributed widely in all the deep fault depressions and it has great. The source rock in K1 d2 is developed mainly in the western fault depressions, the K₁yc source rock in the eastern fault depressions, and the J₃h source rock in the Xujiaweizi and Shuangcheng depressions.