Disclosed is a DC cable thermal cycle voltage test device. The invention relates to a DC cable thermal cycle voltage test device. According to the existing DC cable thermal cycle voltage test device, a cross-under cable heating transformer and an AC heating mode are employed, the electric field distribution is changed when the temperature of a cable is changed, so that test cannot truly reflect the operation condition of the cable. Therefore, the existing DC cable thermal cycle voltage test device is defective. The DC cable thermal cycle voltage test device of the invention comprises a step-up transformer, and a rectifier bridge electrically connected with the step-up transformer. The rectifier bridge has a first output end and a second output end. A DC cable for test is connected between the first output end and the second output end. The high-potential end of the DC cable for test is connected to a DC high-voltage generator. According to the technical scheme, thermal cycle voltage test is carried out under direct current instead of traditional induced alternating current, the actual operation condition of a DC cable can be truly simulated, and test is closer to the actual working condition.