With the depletion of fossil energy, the rise of distributed energy such as wind power and photovoltaic(PV) and the rapid development of power electronics technology, the VSC-DC power distribution network has more potential compared with AC power distribution network.In this paper, firstly, typical operation modes of “hand in hand ” VSC-DC distribution power network are researched. Secondly, switching methods of system control modes is proposed for the cases of disconnection and controllable devices partially out of operation resulting in changes of operation mode, At last,hardware in loop (HIL) tests on RT-LAB including 4 typical operation modes of DC distribution network and smooth automatic switching of system control mode are carried out. The simulation results indicate the effectiveness of the proposed mode switching methods and these methods provide a significant reference for the future research of DC power distribution network.