UPS is an important power supply support equipment. In the process of use, protection is a very important operation, it can well prevent machine failure. In the UPS power supply equipment, in addition to the fan and circuit breaker switch components for cooling, there are a large number of solid-state electronic devices. These electronic devices are in constant use. Although there is no machine wear, they are greatly affected by their surroundings. Therefore, we need to do a good job of temperature control of UPS.