The laser scanning projection system assists workers in assembling by projecting a contour frame on the target surface. Using this system for auxiliary assembly can effectively solve the problems of poor efficiency and low accuracy caused by traditional assembly methods. In order to make the self-developed laser scanning projection system directly read and project the data of complex curves in the digital model. The B-spline curve entity type is analyzed in the IGES (Initial Graphic Exchange Specification) file, and then a method for extracting scanning projection coordinates based on the IGES file and generating a 2D galvanometer scan drive file is proposed. The self-developed laser scanning projection system can be realized to directly read the data of the complex curve in the theoretical model, and the projection accuracy can reach 0.5mm. This method can effectively improve the production efficiency of workshop assembly and make industrial production more intelligent and efficient.