The invention discloses an error test system and method for a current transformer at extreme temperature, and relates to the field of transformer performance test; and the system and method used for evaluating performance of the current transformer for a distribution network. The system comprises an extreme temperature test box, a current transformer error test unit, an adapter bar, a contactor and a connecting wire, under the condition of primary wiring; errors of the current transformer under the conditions of extreme high temperature, extreme low temperature and normal temperature can be tested, test results are automatically calculated, and original records and reports are formed. Manual intervention is not needed, the tested current transformer does not need to be moved repeatedly, operation is easy and convenient, the t labor intensity for test is greatly reduced, the test efficiency and the intelligent degree are improved, and the method is particularly suitable for error testsof the current transformer at the extreme temperature.