The invention relates to a quasi-steady-state based voltage correction control method of a multi-scale AC-DC system, and belongs to the technical field of safety and control of power systems. The quasi-steady-state based voltage correction control method comprises the steps of classifying and integrating fault types of an AC system and characteristics of DC system control and protection devices according to a certain scale in one-to-one correspondence, solving voltage safety margin according to scales, and performing correction control on an out-of-limit voltage by the DC system control and protection device corresponding to each scale. The adjustment characteristic of the DC system control and protection device is fully considered, the voltage adjustment flexibility is improved very wellby a mode that the control and protection devices are in one-to-one correspondence to the faults of the AC system, the voltage control capability is improved to a certain extend compared with a traditional AVC mode, and more importantly, the power grid running economy is improved by a mode of considering action cost.