A novel method of capacitive current measurement is proposed for distribution networks. An adjustable reactor is connected in series with the open-delta secondary of a zero sequence voltage transformer. The distribution network resonance frequency is sought by injecting a current signal with variable frequency. By adjusting the reactor， another resonance frequency is also sought. The distribution network capacitance and capacitive current to ground is then calculated using the two resonance frequencies. The measuring method has eliminated the influence of the voltage transformer leakage impedance on measurement. The measuring device developed has been tested in laboratory and real distribution networks. The results obtained show that the method proposed is highly accurate， capable of testing in real-time， and without interrupting power supply. It can be applied in distribution networks with neutral point unearthed or with Petersen-coil following-setting.