As the core equipment for HVDC transmission system, valve control system is mainly responsible for triggering, monitoring and protecting the converter valve. In Ningdong-Shandong ± 660 kV DC transmission project, the working principle and design features of the valve control system are presented. In addition, the on-site operation is introduced, with focus on the problems of valve base electronics(VBE) occurring in the commmissioning and trial operation. Finally, effective measures and improvement suggestions are proposed.