The model predictive control method of Modular multilevel converter (MMC) is studied, and the inner loop current controller is tuned. Simultaneously, combined with the vector control strategy of the voltage source converter (VSC), the designed inner and outer loop controller is applied to the MMC type DC transmission system. The time domain simulation results show that the potential trends of the AC output terminals of the two bridge arms of each phase of the MMC are consistent, which verifies the effectiveness of the proposed MMC model predictive control method.