The invention relates to a test method for verifying the reliability of a transition joint. Currently, there is no effective and accurate test method for the transition joint. The method comprises the following steps: installing a test loop and a simulation loop; determining a temperature control cable; carrying out a load cycle test of the test loop; carrying out a DC overlapping operation impulse voltage test of the test loop; carrying out a DC overlapping lightning impulse voltage test; and carrying out inspection after testing. According to the technical scheme of the invention, through the temperature monitoring of the simulation loop, the method achieves the accurate control of the wire temperature of the test loop, and improves the accuracy of the testing of the reliability of the transition joint. Moreover, the temperature control cable is determined, thereby facilitating the improvement of the testing safety, and enabling the test to be carried out smoothly.