The invention presents an adaptive filtering method for the DC ripple of a high-voltage cascaded H-bridge SVG, which is used to filter the ripple component of the DC capacitor voltage feedback signalof a high-voltage cascaded H-bridge SVG arranged in a power grid. The adaptive filtering method includes following steps: tracking and acquiring the real-time frequency of the power grid; lag-samplingthe DC capacitor voltage according to the acquired real-time frequency of the power grid to acquire a lag-sampled DC capacitor voltage; and filtering the ripple component of the DC capacitor voltagefeedback signal based on the acquired lag-sampled DC capacitor voltage, so as to obtain a DC capacitor voltage with the double-frequency ripple component removed. The method is simple in design and easy to realize in engineering. In the process of feed-forward compensation (elimination) of double-frequency voltage fluctuation, the function of coverage compensation (elimination) for other high-order harmonics is also achieved.