Title: Anatomical Structure-Aware Image Difference Graph Learning for Difference-Aware Medical Visual Question Answering. Abstract: To contribute to automating the medical vision-language model, we propose a novel Chest-Xray Different Visual Question Answering (VQA) task. Given a pair of main and reference images, this task attempts to answer several questions on both diseases and more importantly, the differences between them. This is consistent with the radiologist's diagnosis practice that compares the current image with the reference before concluding the report. For this task, we propose a new dataset, namely  MIMIC-Diff-VQA including 700,821 QA pairs on 109,872 pairs of images. Meanwhile, we also propose a novel expert knowledge-aware graph representation learning model to address this problem. We leveraged the expert knowledge such as anatomical structure prior, semantic and spatial knowledge to construct a multi-relationship graph to represent the image differences between two images for the image difference VQA task. Our dataset and code will be released upon publication. We believe this work would further push forward the medical vision language model.