A segmentation method and segmentation apparatus are provided, where the segmentation method includes receiving image frames comprising a current frame and an adjacent frame to the current frame, determining a feature map to aggregate the image frames based on temporal information between the current frame and the adjacent frame, extracting a feature of a region of interest (ROI) corresponding to instances included in the current frame from the feature map, predicting a class of an object corresponding to the ROI based on the feature of the ROI, and segmenting the instances by correcting an amodal mask predicted corresponding to the class of the object based on the feature of the ROI.