The invention provides a lightning arrester testing support in a high-voltage cabinet, and relates to the field of lightning arrester testing. The lightning arrester support comprises an insulting supporting frame and an insulating height-rising supporting column, the insulting supporting frame is placed between a voltage transformer and a copper bar, the undersurface of the insulting supporting frame is provided with an accommodating groove which is matched with the insulating height-rising supporting column, and the insulating height-rising supporting column is placed in the accommodating groove. During a test, a lightning arrester can be directly connected to the copper bar and placed on the testing support, wherein the height of the testing support can be adjusted through the insulating height-rising supporting column so that an appropriate position can be found, thus the testing requirement can be met, there is no need for two persons to place an insulating shielding object in a narrow space, thus the testing time is saved, and the testing efficiency is improved; the insulating height-rising supporting column is directly placed on the accommodating groove of the insulting supporting frame, thus good stability can be supplied, the testing support is guaranteed to be supported steadily, in the testing process, the situation that the lightning arrester slips off while being connected to the copper bar cannot occur, the equipment and personal safety is guaranteed, and thus the lightning arrester testing support has great practicability and market popularization value.