The invention discloses a dynamic optimization scheduling method and system for a flexible interconnected distribution network. A dynamic optimization scheduling method of a flexible interconnected distribution network based on model prediction control is provided for the uncertainty of renewable energy output and load demands by taking a flexible interconnected distribution network connected witheach feeder through a multi-terminal back-to-back VSC-HVDC. The method comprises the steps of: based on the renewable energy and load ultra-short term power prediction information, establishing a voltage prediction model through calculation of voltage sensitivity of each node, establishing a flexible distribution network optimization operation model to take the minimum of the deviation of a predicted voltage and a rated voltage and the integrated power supply cost by a target, and combining a method of adaptive dynamic weight and feedback correction to optimize and obtain a dispatching instruction value and perform issuing. The method can effectively solve the problem of voltage out-of-limit generated by random fluctuation of the distributed power supply output and load demands and effectively balances the economical efficiency and the safety of the operation of the flexible interconnected distribution network.