The invention discloses a multi-port converter suitable for the series connection of a composite energy storage medium. The multi-port converter comprises at least two energy storage media connected in series, a power circuit connected with the energy storage media in parallel, and a filter circuit connected with the power circuit in parallel. The power circuit comprises a three-phase bridge arm and a bidirectional switch for controlling the output of each phase of bridge arm, and each phase of bridge arm comprises at least two reverse conducting power switch tubes; and the filter circuit is an LCL filter. By reasonably controlling the on-off of the power device, the cooperative work of the two energy storage media can be realized, the advantages of the two energy storage media in the energy storage converter can be fully played, the advantage complementation of the two energy storage media can be realized, the service life of the energy storage media can be prolonged, and the economicoptimization can be realized.