Given the current difficulties to remove faults in DC transmission system and high complexity for the system to restart after faults, a method to suppress the DC pole-to-pole fault current is proposed for half- and full-bridge based cell-hybrid modular multilevel converter (MMC). Firstly, the suppression voltage used to suppress the fault current is computed according to modulation margin of system. Then considering the fault current, if it is larger than the upper limit value, the phase cascaded voltage is controlled as a negative suppression voltage. If the fault current is smaller than the lower limit value, the phase cascaded voltage is controlled as a positive suppression voltage. If the fault current is between them, the phase cascaded voltage is controlled as zero, and the valve is equal to two STATCOMs in parallel which can provide reactive power for the grid. This method is simple to carry out and can limit the fault current in a given period quickly by not blocking the valve. Finally, a two-terminal MMC-HVDC transmission system is constructed in PSCAD/EMTDC, and simulation results show that the method mentioned above is correct.