The invention relates to the field of automobile manufacturing and measuring, in particular to an automatic color marking method and device. The automatic color marking device comprises a dotting module, a controller, a conveying and positioning module, a CCD image analysis system and a safety system module. The dotting module is used for dotting and is composed of a servo motor, a rotation shaft, a rotation disc, three transmission air cylinders and three color mark pens. The controller is achieved through a PLC, the conveying and positioning module is used for conveying and positioning products and composed of a conveying air cylinder and a triangular window mold film, and the CCD image analysis system is used for collecting and analyzing product images. According to the automatic color marking method and device, operation errors are reduced, operation precision is high, automatic color marking in production is achieved, the production efficiency is improved, the labor cost is reduced, the online detection function is achieved, and accordingly influences on production are avoided.