Regarding of discrete manufacturing enterprise production process of slewing mechanism as an example of study, value stream mapping technology is applied to carry out the optimization of manufacturing process. A chart was drawn about current situation of value stream of product manufacturing and existing non-value-added activities were found by carrying out production process analysis and field data collection for product manufacturing procedure in a workshop. Using the method related to basic industrial engineering, the corresponding improvement measures were put forward for practical manufacturing in an enterprise, and a future value stream mapping was plotted. Through the workshop layout, personnel adjustment, it not only reduces the work-in-process inventory, shortens delivery cycle but also enhances the efficiency of the staff morale and processing, let the enterprise harvest great economic benefit.