The invention discloses a large-scale grounding grid high-frequency characteristic test method using grounding grid current reflow. The method includes the following steps that: the position of a current injection point and a current reflow point are selected from a grounding grid, the current injection point is connected with the positive pole of a high-frequency power source, and the current reflow point is connected with the positive pole of the high-frequency power source; a voltage reference point is selected from a section between the current injection point and the current reflow point;a high-voltage probe is used to measure potential difference between the current injection point and the voltage reference point when high-frequency current is injected into the grounding grid, the effective value of the potential difference is read, namely, ground potential rise of the injection point can be obtained; a current probe is adopted to measure the effective value of the high-frequency current, phase difference between the current and the ground potential rise is obtained through comparison; the high-frequency grounding impedance of the grounding grid under a certain frequency iscalculated according to the ground potential rise, the current and the phase difference; and the frequency of the high-frequency power source is changed, the above steps are repeated, so that the frequency-impedance feature of the grounding grid can be obtained.