Abstract: From the duration of the task and real time capability, the fundamental performance of the density feedback control system (DFCS) in HT-7 superconducting Tokamak equipment was analyzed. The system based on Windows and VxWorks was compared with that based on Windows and Linux. The results show that the DFCS based on Windows and VxWorks has a better real time capability, a better control effect and a more steady control process.