The utility model provides a hierarchical formula DC voltage initiative adjusting device for flexible direct current transmission relates to flexible DC transmission technology field. The device includes the initiative of rectifier unit, fault protection step up in grades unit, inverter unit, current measurement signal conditioning circuit, voltage measurement signal conditioning circuit, IGBT drive unit, detection the control unit and LC filtering unit, and rectifier unit 0 rectification rectifier unit 1 value appears fluctuating and not during 1.5 times of rectifier unit 2 when voltage, and the rectifier unit 3 coefficient that steps up in grades at any time. The utility model discloses utilizing the capacitor bank that fault protection initiative was stepped up in the unit in grades to charge, judging rectification side output voltage value and come controlled access electric capacity number, the control coefficient that initiatively steps up carries out difference the stepping up of coefficient of stepping up to different voltages, can be under normal operating and grid voltage fluctuation state, and the reduction fluctuation voltage is to the impact of equipment, can effectively restrain the fluctuation voltage instantaneous peak value, avoids it to cause the damage to the design.