Insulator zero tester

The utility model discloses an insulator zero tester, which comprises a measurement fork, a plurality of discharge gaps, an insulation board and an insulation rod. The measurement fork and the discharge gaps are arranged on the insulation board, the insulation board is connected with the insulation rod, the measurement fork is electrically connected with the discharge gaps, and a discharge sensing alarm device which can sense discharge voltages among the discharge gaps is also arranged between the insulation board and the insulation rod. Since the discharge sensing alarm device is arranged between the insulation board and the insulation rod, the insulator zero tester can shield faradic electricity of a substation and can also sense the discharge voltages among the discharge gaps, namely discharge voltages at the two ends of an insulator, thus dual insurance is provided for judgment of zero testing and the testing accuracy is greatly improved.