The utility model relates to a to the device that circuit component carries out the incorrect connection test, concretely relates to portable current transformer polarity test appearance, including last, lower casing, on, the internal test circuit that sets up of inferior valve, test circuit includes power module, the power module discharge power supply that connects in parallel, starting switch concatenates between the positive negative pole of discharge power supply, potentiometre and the current transformer positive and negative binding post that once inclines, correspond the current transformer positive and negative binding post of positive and negative connecting terminal setting current transformer secondary side that once inclines, testing element concatenates between the positive and negative binding post of current transformer secondary side, a power supply modul, the discharge power supply, the potentiometre, starting switch and current transformer once incline positive and negative binding post and fix under on the casing, lower casing correspondence sets up the braces, be equipped with the decompression gasbag on the braces, testing element and the positive and negative connecting terminal setting of current transformer secondary side are on last casing. The utility model discloses simple structure, easy and simple to handle, test directly perceived, light portable, safe and reliable.