The multi-terminal flexible DC grid has an important role in integrating renewable energy owing to its excellent advantages. However, the current flow in a multi-terminal flexible DC grid cannot be controlled flexibly, so a current flow controller is required to improve the distribution. Therefore, this paper presents a new topology of current flow controller suitable for a multi-terminal flexible DC grid. It has the advantages of low implementation cost, wide adjustment range, and low operational power loss. The current flow controller uses the switch to dynamically insert the capacitance and resistance to change the line equivalent resistance. This realizes the current flow control function. The control system including voltage limiting link and current difference gain link is designed to reduce the implementation cost and operational power loss. Finally, the effectiveness and feasibility of the proposed DC current flow controller are verified by electromagnetic transient simulation and low voltage physical experiment. This work is supported by the National Natural Science Foundation of China (No. 52077124).