Disclosed is a method for structuring a comparative reference value used to estimate a residual charge (SOC; State of Charge) of a battery. The method comprises comprising steps of: measuring open circuit voltages (OCV) and residual capacities (SOC) of a battery at various temperatures and tabling them according to the temperatures; measuring an open circuit voltage (OCV1) at a temperature before a test; carrying out a discharge capacity counting (Ah-counting) for the battery using a measurement apparatus while carrying out a dynamic pattern test; providing a sufficient relaxation time period for the battery after ending the dynamic pattern test; measuring an open circuit voltage (OCV2) at a temperature after the sufficient relaxation time period; obtaining residual capacity values of the battery corresponding to the measured open circuit voltages (OCV1, OCV2) from the table; assuming a difference between the above-obtained two residual capacity values as a .delta.SOC and calculating an 1C-rated capacity based on the .delta.SOC; and applying the calculated rated capacity as a denominator of the discharge capacity counting to calculate an exact residual capacity of the battery.