The arc orbit rotary control system is primary components of the rotary balances set, simulating non-dimensional rotary parameter in spin of airplane. The constituent parts of control system are frequency conversion electric machine, frequency converter, monitor system and so on, by network communicated and modified frequency converter parameter setting up, multi-position monitor system has been realized by computer management, computer monitoring, touch screen and frequency converter. After the debugged and operated, net worked real-time monitoring, though run, it was very stable, high degree of automation. Through experiment and application index, the control system have been met the special requirements of rotary balances test.