The Manning Formula is an empirical formula calculating the channel flow or speed.The Civil 3D software uses a custom tag expression to link the Manning Formula to a certain tag, so that the Manning Formula is able to be seen the gains, same as the the basic data of pipe network parts.Based on a practical project case study, this paper applies the software of AutoCAD Civil 3D to label the pipeline network in plane to show its flow value.Results shows that the AutoCAD Civil 3D possesses great advantages in applying the Manning Formula to optimize pipe network design and check parts in pipeline network parts.