The invention provides a modular multilevel-based STATCOM device for inhibiting ripples of capacitive voltage. The STATCOM device comprises an STATCOM system which is directly connected to a common node through a connection inductor in parallel, wherein the STATCOM system comprises a bridge arm phase A, a bridge arm phase B, a bridge arm phase C and a bridge arm phase D. On the basis of an MMC topology, the DC bus voltage of the MMC is eliminated, the hidden danger of a short circuit of a common bus of a DC side is eliminated and the security of the device is improved; the low-frequency ripples of capacitive voltage of an upper bridge arm and a lower bridge arm of each bridge arm phase are inhibited by using a low-voltage and low-capacity capacitor, so that use of lower capacitance of a sub-module is facilitated, the cost of a system is reduced and the volume of the device is reduced. The bride arm phases of switching devices are replaced with buffer inductors, the quantities of the capacitors and the switching devices are reduced to 3/4 of those of a conventional structure, so that the cost and the volume of the device are significantly reduced and the loss of the system is reduced. The application of the bridge arm phase is not limited to the application scene of reactive power compensation and an existing bridge arm phase adopting cascaded H-bridge multilevel topological devices can be replaced.