Image lossless labeling method and system

The invention discloses an image lossless labeling method and system. The method comprises the steps that 1, a web server side receives an image to be labeled, and the image is transmitted to a browser side; 2, the browser side sets a canvas element to load the image to be labeled; 3, the browser side monitors mouse clicking events in real time, information associated with the mouse clicking events is collected and transmitted to the web server side, and each mouse clicking event is associated with a to-be-labeled point in the image to be labeled and corresponding labeling information; 4, the web server side dynamically labels a labeling point associated with the mouse clicking events and the corresponding labeling information in the image to be labeled, the dynamically labeled image is transmitted to the browser side and dynamically loaded through the canvas element, and therefore lossless labeling of the image is achieved.