Background: Manual landmarking is a time consuming and highly professional work.Although some algorithm-based landmarking methods have been proposed, they lack flexibility and may be susceptible to data diversity. Methods: The CT images from 66 patients who underwent oral and maxillofacial surgery (OMS) were landmarked manually in MIMICS. Then the CT slices were exported as images for recreating the 3D volume. The coordinate data of landmarks were further processed in Matlab using a principal component analysis (PCA) method. A patch-based deep neural network model with a three-layer convolutional neural network (CNN) was trained to obtain landmarks from CT images. Results: The evaluating experiment showed that this CNN model could automatically finish landmarking in an average processing time of 37.871 seconds with an average accuracy of 5.785 mm. Conclusion: This study shows a promising potential to relieve the workload of the surgeon and reduces the dependence on human experience for OMS landmarking. K E Y W O R D S 3D cephalometry, automatic landmarking, convolutional neural network, machine learning, oral and maxillofacial surgery