The invention discloses a method for evaluating the voltage supporting ability of a multi-direct current feed alternating current power grid provided with a dynamic reactive power compensation device. The method includes the following steps that: S1, a node admittance matrix of the alternating current power grid is established; S2, the node admittance matrix of the alternating current power grid is modified, so that a node admittance correction matrix can be obtained; S3, a node impedance matrix which is included into the influence of the dynamic reactive power compensation device is calculated; S4, voltage supporting ability evaluation indexes at direct current transmission system feed nodes to be investigated are calculated according to the node impedance matrix which is included into the influence of the dynamic reactive power compensation device; and S5, the voltage supporting ability at the direct current transmission system nodes to be investigated is evaluated according to the voltage supporting ability evaluation indexes and based on evaluation threshold values. With the method of the invention adopted, the node impedance matrix which is included into the influence of the dynamic reactive power compensation device is calculated, and therefore, the voltage supporting ability of the existing alternating current power grid which is provided with the dynamic reactive power compensation device can be reflected correctly, and decision-making support can be provided for the planning and operation of the power grid.