The invention relates to the technical field of copyright image protection, and provides a decentralized image copyright protection system and method with infringement real-time detection, and the method comprises the following steps of (1), enabling a registered user to upload an image through a client, and enabling an SIFT image feature extraction algorithm in the system to carry out the featuredata collection on the uploaded image; (2) extracting the invariant characteristics, such as visual angle, translation, affine, brightness, rotation, etc., of an existing copyright image by a user through an SIFT algorithm to form a local feature vector set of the image, and taking the local feature vector set as a registered image feature data set; (3) carrying out distributed storage on the feature data sets in the steps (1) and (2) by utilizing an IPFS (Internet Protocol File System), and constructing a network transmission protocol for persistent and distributed storage and file sharing;and (4) performing comparative analysis and calculation, and judging that the image does not accord with the condition of forming a new work. The system and the method provided by the invention have the characteristics of being tamper-proofing, realizing the high safety, permanent preservation and decentralization, being able to trace, being low in cost, etc.