The embodiment of the invention provides a self-adaptive voltage-sharing device which is used for shielding a tip local strong electric field on a high potential end of a test device. The a self-adaptive voltage-sharing device comprises a voltage-sharing mechanism adjustable in size, arranged on the high potential end of the test device and used for shielding the tip local strong electric field on a high potential end; a compressed air driving device connected with the test device and communicated with the voltage-sharing mechanism through an airflow channel in a high voltage sleeve so as to adjust the size of the voltage-sharing mechanism by means of air charging and air discharging; and an electric quantity parameter measuring unit used for measuring electric quantity parameters of the high potential end of the test device high voltage sleeve and the voltage-sharing mechanism so as to subsequently drive the compressed air driving device to adjust the size of the voltage-sharing mechanism according to the electric quantity parameters until the electric quantity parameters measured by the electric quantity parameter measuring unit are within expected ranges.