The invention discloses a splicing method for measuring image data with large forgings assisted by lasers, and belongs to the field of image processing and computer vision detection. The method comprises the steps that two different laser devices are used for constructing feature points on a metal surface, and the image data can be spliced under complex working conditions; two sets of adjacent binocular cameras carry out image data rough matching through light spots projected by point laser devices, meanwhile, a conversion matrix is obtained, linear laser devices are used for projecting grids, the rough matching conversion matrix is adopted as an initial value, image data fine matching is carried out, and splicing is achieved after redundant data are removed. The three light spots of different sizes are adopted as feature points in image data rough matching, error matching is effectively avoided, and matching precision is improved. The conversion matrix obtained through rough matching is adopted as the initial value in fine matching, and the computation quantity of correcting the conversion matrix is reduced. In the splicing process, a measurement system is taken as a multi-binocular measurement system, the method has no precise requirement for the position of a target, and implementation is easy.