Outdoor winter temperatures in other northern regions such as Heilongjiang Province are relatively low. As an important equipment of ensuring the safety of transmission lines, the stability of the condition monitoring devices is facing great challenges. In order to ensure that the condition monitoring device can operate reliably in winter, so as to avoid the influence of low temperature in winter on the reliability of the condition monitoring device, in this paper a device is designed that uses solar heat for heat preservation for power equipment condition monitoring device. The device uses an all-glass vacuum solar collector tube to convert solar energy into heat, and realizes instant feedback and control of temperature through a bimetallic temperature sensor. After testing, in winter, the internal temperature of the heat insulation box can be increased by about 30°C compared with the outside, which can effectively improve the winter operating environment of the device.