摘要： Image processing technology has many applications, such as medical image processing, face detection and vehicle detection. At present, in the field of civil engineering, there are many difficulties in the intelligent manufacturing process of precast concrete elements (PCEs), such as non-contact measurement of PCEs using 3D laser scanners. In order to solve the data acquisition problem of PCE data in outdoor laser scan data, this paper is the first attempt to map a 3D laser scan data into 2D images, and then use image processing technology to realize the segmentation of outdoor laser scan data which contains the PCE data. We convert the processed objects from laser scan data to images, and computation time is reduced effectively as a result. This segmentation technique includes four steps, data preprocessing, 3D laser scan data mapping into 2D images, image processing for segmentation and laser scan data processing. Finally, the results obtained by experiments prove the effectiveness of this segmentation technique.