Micro-grid is one of the effective means to absorb distributed generations; however, this also results in issues of voltage instability and difficulty in operation controlling of the micro-grid, especially the unbalanced three-phase voltage at the point of common coupling (PCC). This paper proposes a control for micro-grid voltage bipolar compensation at the point of common coupling, the upper level sends the control signals, these control signals relate to the positive-and negative-sequence components of the unbalanced voltage, dual the current control loop current setpoint is obtained. The lower control loop controller through dual current implementation, in view of the PCC point of three-phase voltage imbalance problem, application of dq rotating coordinate decomposition principle, proposed dual synchronous coordinate system based on improved decoupling phase-locked loop (IDDSRF-PLL) to independently control the positive and negative sequence voltage component. Furthermore, the three-phase balance voltage could be achieved by controlling the model of positive and negative sequence currents, and using the unbalance voltage compensation controller, bus voltage doubler fluctuation at point of common coupling is zero, thus realizing the three-phase control voltage unbalance compensation. MATLAB/Simulink software is used to set up the simulation model of connecting micro-grid to the main grid. The simulation results show that the hierarchical control method is effective to implement voltage control of micro-grid.