Abstract: In Nanjing Hydraulic Research Institute (NHRI), the NHRI-400 g·t centrifuge has been operated for more than twenty years since established and put in use in 1991. It is one of the oldest machines in China. In 2016 and 2017, the machine was thoroughly upgraded without changing its basic engineering facilities. Upgradation is made mainly to the mechanical system, electrical system and data acquisition system. A torque motor and a matched driving control system are employed to drive the machine directly, rather than the traditional DC motor-reducer drive system. Also, the new data acquisition system includes 90 static data channels and 38 dynamic data channels. The upgraded NHRI-400 g·t geotechnical centrifuge has been served in several projects and performed well.