The invention discloses an MMC hybrid bridge arm topology structure with the ability of direct current side short-circuit current blocking, which belongs to the technical field of power electronics. The MMC bridge arm is composed of two kinds of sub-modules mixed in a certain proportion, and has buffer inductance. According to the output characteristic of different types of sub-modules of MMC, three-level double half bridge sub-modules and four-level series twin sub-modules form the hybrid bridge arm in a design proportion, which reduces the number of sub-modules and the number of peripheral devices at the same voltage level. The number of the sub-modules is designed, and at the same time the ability of direct current side short-circuit current blocking is realized. The number of controllable devices is reduced. The cost and loss of a converter are reduced. The overall efficiency is improved. In normal operation, two kinds of sub-modules share similar control, and the design of a control algorithm is relatively simple.