The invention discloses a test device for directly measuring the leakage current of a test sample and wirelessly outputting data. The test device comprises a host computer, a DC high-voltage generator, a high-voltage test wire, a current acquiring module, and an insulated support structure. The top end of the high-voltage test wire is connected with the current acquiring module. The bottom end of the high-voltage test wire is connected with the DC high-voltage generator. The current acquiring module is connected with a semicircular metallic hook. The bottom end of the current acquiring module is connected with the high-voltage test wire. The lower part of the current acquiring module is fixed to the top end of an insulated hollow cylinder. The insulated hollow cylinder on the upper part of the insulated support structure is supported on the side surface of the test sample in virtue of an insulated support. The bottom end of an insulated support rod on the lower part of the insulated support structure is supported on the ground. A top binding post of the DC high-voltage generator is connected with the bottom end of the high-voltage test wire. The test device may prevent the leakage current of a test wire from influencing the accuracy of a test result and reduces an electric shock risk of electrical test workers.