Multiple AC feeders in urban distribution network usually apply closed loop connection and open-loop operation mode, and do not have controllable power support between lines. The flexible interconnection of multi-circuit 10 kV lines by back-to-back multi-terminal converter can transform the open-loop operation mode of traditional distribution network into closed-loop operation mode. Based on balanced load strategy, a DC power real-time modulation technology is proposed for multiple 10 kV lines with flexible interconnection to DC distribution center, which uses active power distribution coefficient of feeder to realize active power deviation control and load balancing among multiple lines. A flexible interconnected AC/DC power distribution system based on DC distribution system with four terminal hybrid module MMC is constructed by using PSCAD/EMTDC simulation software. On the basis of master-slave control, the control strategy of DC distribution center is improved by using power modulation technology based on load balancing strategy. The simulation results show that the proposed DC power modulation strategy can balance the load between the feeders in real time and improve the equipment utilization and operation reliability of the AC distribution network under the condition of reducing the load measurement points of the distribution power system.