A distributed voltage unbalance compensation method for micro grid groups comprises the following steps: converting the voltage v of a common coupling point into voltages v and v in a rotating d-q coordinate system through Park transformation, and using a low-pass filter LPF to extract the positive and negative sequence components v<+> and v<-> of the voltage of the common coupling point in the rotating d-q coordinate system; transmitting signals to a secondary controller, and calculating the voltage unbalance VUF; taking the error of comparison between the calculated valueVUF of voltage unbalance and the reference value VUF* of voltage unbalance as the input signal of a proportional-integral PI controller; and finally, multiplying the output signal by the negative sequence component v<-> of the voltage of the common coupling point, and transmitting a generated unbalance compensation reference value UCR to a primary controller. The method has an obvious effect in compensation of voltage unbalance of the common coupling point, and shows strong robustness in dealing with output power fluctuation and load sudden change of a power supply.