Hydraulic torque converter is one of important parts of automobile. Application of Manufacturing Execution System (MES) in workshop of hydraulic torque converter can improve the agility of manufacturing system. Hydraulic torque converter assembly manufacturing system is a typical discrete and mixed model assembly manufacturing system. On the basis of demand and characteristics of hydraulic torque converter assembly manufacturing system, the steps of implementation of MES were put forward. The structure of hydraulic torque converter workshop in MES was constructed. The key technology of the building of MES was analyzed, which provides a way for an enterprise to build MES.