Abstract: Through the combination of PERT technology and process reengineering theory, each stage of project implementation is regarded as a process, ECRS analysis method is taken as the general method and step of project management process reengineering, and PERT technology is emphasized as a quantitative tool to effectively solve the problem of no quantitative comparison before and after traditional process reengineering. Finally, a construction supervisor in northern China is taken as a practical case. The results show that the reconstruction method is simple in operation, the reconstruction process can be adjusted from multiple angles, the reconstruction effect can be quantified and tested, and the operation is strong. It is suitable for solving the practical contradiction of fewer managers and more projects under the trend of flat organizational structure, and finally realizing the efficient operation of organizational system and high-quality development of business work.