Abstract: The battery in the substation can provide energy for the power supply system, the safety of the battery is very important. Lead-acid batteries are commonly used, but its voltage is instability, capacity decays very quickly, low temperature performance is poor. This paper compared lead-acid battery with lithium ion battery, analyzed their cycle performance, energy density, temperature performance, safety performance and economy, offered a proposal of replacing lead-acid battery with lithium ion battery, provided a theoretical guidance for selecting the most suitable power supply system for substation.