MMC module circuit with ability is blocked to direct current side trouble. Relate to electric power system protection control field. Locking short -circuit current completely, simple structure, required device is few, the integrated level is high. Including two half -bridge submodule pieces, take the power switch pipe no. 1 and the diode of reverse parallel connection diode. One half -bridge submodule piece with take the projecting pole of the power switch pipe no. 1 of reverse parallel connection diode to connect, another with take the collecting electrode of the power switch pipe no. 1 of reverse parallel connection diode to connect. Take the collecting electrode of the power switch pipe no. 2 of reverse parallel connection diode to connect in the half -bridge submodule piece that the negative pole of diode and the projecting pole of power switch pipe no. 1 with taking the reverse parallel connection diode are connected, the power switch of taking the reverse parallel connection diode in anodal and another half -bridge submodule piece is managed three projecting pole and is connected. The product is small, and stability is high, topological structure is simple, and is with low costs, the easy realization, the configuration is nimble, reduces the consumption, the time can break off direct current side, the response is rapidly.