Electrolytic capacitors are essential key components of energy storage and power conversion in the switching power supply products. However, relative to the other electronic components, life prediction for them is shortest in high ripple current and high-temperature power conversion applications. Thus, electrolytic capacitor restricts the electrical life of the product. First, based on the internal structure and the failure mechanism of electrolytic capacitor, this paper points out that temperature is the most important factor in the evaporation rate of the electrolyte, and analyzes the influences of ambient temperature and ripple current on the life of electrolytic capacitor respectively. Finally, taking the PFC bus electrolytic capacitor of 240 W high-frequency switching power supply prototype for example, the estimated life of capacitor meets the requirements of product specification through two ways to measure capacitor internal temperature.