The invention relates to a modular DC transformer based on a discrete switched capacitor. The modular DC transformer comprises one or more DSC- DAB sub-modules, input ends of the plurality of DSC-DABsub-modules are connected in series or in parallel, and output ends are connected in series or parallel. The DSC-DAB sub-modules comprise discrete switched capacitor modules, medium / high voltage DC conversion modules, high-frequency isolation conversion modules and low-voltage DC conversion modules which are connected in order. According to the invention, the modular design is adopted, the voltagechange speed of a high-frequency link is reduced, the overcurrent caused by the parasitic capacitance of the transformer is avoided, at the same time, the volume of the DC transformer is reduced, theproduction cost of the transformer is reduced, and the work such as installation, commissioning and transportation is facilitated.