The invention discloses a client image blurring deduplication method supporting the proprietary authentication. The method mainly aims to solve the problems that an existing deduplication technology is low in accuracy and safety. The method includes the steps that 1, whether an image similar to a to-be-deduplicated original image exists on a server terminal or not is detected, if yes, 'proprietary authentication' is conducted, and if no, deduplication is not conducted; 2, a server conducts the 'proprietary authentication' on the original image, if the authentication is successful, quality comparison is conducted, and if the authentication fails, deduplication is rejected by a client; 3, the server determines whether the quality of the original image is larger than that of the similar image by comparison, if yeas, a link of the similar image is returned to the client, and if no, the original image is uploaded and stored in the server terminal. The method improves the accuracy of repetition detection, ensures the security of the 'proprietary authentication' , therefore, the server terminal can retain the image with good quality, and the method can be used for deduplication of the similar image.