Abstract: ‍ ‍Passive forensics of digital images is a technique that identifies the authenticity， localize the spliced regions and analyzing the history of tampering by using the inherent properties of images. As most images are JPEG compressed for storage and transmission， passive forensics of digital images based on JPEG format has attracted more and more attention. In order to more comprehensively summarize existing methods， this paper emphatically introduces JPEG image related forensics approaches， discusses the key technologies of double JPEG compression detection， quantitative matrix estimation and splicing detection and location in detail， analyzes the main issues and faced difficulties of existing methods， prospects for the future development directions.