The present disclosure discloses a multi-path image processing apparatus. An image merging circuit is configured to receive image frames that at least one of the image frames has a largest row number, generate redundant pixel row for each of the image frames that has a row number smaller than the largest row number such that the row number of each of the image frames equals to the largest row number, generate redundant pixel columns for each of the image frames having the number thereof determined by a size of a largest operation window, and merge each two of the image frames through the redundant columns thereof to generate a merged image frame. An image processing circuit performs image processing procedure on the merged image frame to generate a processed merged image frame, wherein at least a part of the image processing procedure is operated according to the largest operation window. An image segmentation circuit segments the processed merged image frame to generate processed image frames.