To meet the requirements of the “Xia-Shang-Zhou Chronology” Project, Peking University AMS facility updated the control system of the PKUAMS by using the ControlNet system product, Group3 Ltd, New Zealand. The upgraded control system consists of a PC-based Loop Controller (LC), six Device Interfaces (DI) and several adequacy signal conditioners. The operation software is written by LabView® (for Windows® 3.X). After a half year operation, the upgraded control system shows better performance, even though it has suffered serious terminal sparks and the frequent sparks from the ion source. The control stability is better than 0.1% for 8 hours and the precision is better than 0.05%.