DC fault current limiter (FCL) is a key device for suppressing DC short-circuit fault currents,which is important in AC/DC hybrid grid. In this paper,topology of a multifunctional modular DC FCL is proposed,which consists of multiple series-connected power electronic modules. On the basis of analyzing its working mechanism,three functions of fault current limit,energy release and DC grid voltage support are realized. The operation mechanism of the multifunctional modular DC FCL is analyzed in detail. A typical configuration scheme is presented for its application in AC-DC hybrid grid. The design of control strategy is completed for the three functional corresponding operation modes. In order to verify the effectiveness of the topology and control strategy,a multi-case simulation model is constructed in Matlab/Simulink. The simulation results show that the proposed modular DC FCL topology and control strategy satisfy the requirements for fault current limiting applications under various fault conditions in AC/DC hybrid grid.