A cascaded STATCOM ( static synchronous compensator) used in industrial and distribution network is designed and studied in this paper，using phase shift carrier pulse width modulation control strategy． A novel ze-ro sequence voltage injecting control method of cascaded STATCOM based on DC side energy is proposed in this pa-per． Based on the interaction of zero-sequence voltage and compensating current，an active power exchange among the three-phase is established which can average the DC side effect caused by unbalanced components． Negative over-current of compensator can be avoided and the cluster’s DC side capacitor voltage balance can be maintained with the assurance of tracking the compensating current． Simulation and experimental results proved that the asym- metrical compensation response speed and precision of cascaded H-Bridge topology can be improved and the topolo-gy control under asymmetrical voltage and unbalanced load is realized． Simulation and experimental results proved the accuracy and rapidity of the proposed method．