Disclosed is a method for setting an initial SOC value, which initializes the SOC in consideration of not only the temperature change of the external environment of the battery but also the internal temperature change of the battery before the battery reaches a stable unloaded state, thereby enhancing the accuracy in the setup of the initial SOC value. The method includes: measuring internal temperatures of the battery and SOCs corresponding to voltages of the battery, which change according to the time passage after a loaded state is converted into an unloaded state, and constructing an SOC estimation table by using measured values, and storing the SOC estimation table; measuring the internal temperature and the voltage of the battery when estimation of an initial SOC value of the battery is required; and reading an SOC corresponding to the measured internal temperature and the voltage of the battery from the SOC estimation table.