The present invention discloses a flexible direct current converter direct current fault current suppression method. The method comprises the steps of: superposing the output amount of a direct current basic controller and the output amount of a direct current optimal controller to obtain a converter phase unit direct voltage control amount initial value; dividing the converter phase unit direct voltage control amount initial value by a converter power module capacitor voltage rated value, and then multiplying a power module capacitor voltage rated value after amplitude limiting link processing to finally obtain a converter phase unit direct voltage control amount final value. After a metallicity direct current short-circuit fault and a high-resistance direct current short-circuit fault isgenerated, the flexible direct current converter direct current fault current suppression method cannot depend on any complex fault detection methods, can automatically and rapidly reduce the converter direct current bus voltage and can allow the converter direct current bus voltage to automatically match the voltage of the fault point so as to reduce the direct current fault voltage peak value,allow the converter to safely pass through the direct current faults and allow the converter to continuously transmit part of the direct current power in the high-resistance fault.