The invention relates to a novel static var compensator based on a VIENNA rectifier, which comprises a plurality of single-phase and three-phase main power circuits composed of a plurality of modularunits cascaded, and a plurality of filter branches which are in parallel to the main power circuit and composed of inductors and capacitors connected in series. The novel static var compensator basedon a VIENNA rectifier in the invention has the advantages that the proposed novel static var compensator has the advantages of fast SVG dynamic response speed, low harmonic content, low power consumption, small volume, light weight, simple SVC control and low price at the same time. The novel static var compensator circuit is formed based on a VIENNA rectifier with energy unidirectionally transmitted and not only can provide advanced fundamental reactive power but also filter out the lower harmonics together with the filter branch connected in parallel to the cascaded VIENNA rectifier and composed of a plurality of inductors and capacitors in series; by controlling the input current of the cascaded VIENNA rectifier, continuous adjustable reactive power can be provided for the system, and the grid current harmonics are suppressed or eliminated.