Shuangshi ( Zhangjiagang )  fine  chemical  company owns a SIEMENS made powed high pressure turbinet. The equipment has not been overhauled yet since operation. Due to the fact that the original factory (SIEMENS) cannot meet the user's requirements, therefore, the user commissioned our company to overhaul for the turbine. There are two major problems in the overhaul of the unit: 1. There was no necessary information and data; 2.The high temperature and high pressure unit is difficult to assembled and disassembled. But we have completed the on-site overhaul work successfully which relies on our unique advantages. As HTC has introduced and digested SIEMENS steam turbine technology for many years. Depend on our rich experience in the field of overhaul, we complete the overhaul successfully. On the other hand, the repaired part s of the turbine in our workshop and the high-speed dynamic balancing test of the rotor were conducted well at the same time, which well supported the on-site overhaul of the unit.