A method for estimating a state of charge of a secondary battery using a full charge capacity of the battery, the method comprising: measuring voltage and current of the battery; calculating the FCC using a voltage change and a current integral of the battery during a specific time; estimating a time remaining until the battery is fully discharged using the calculated FCC and the measured voltage and current to calculate a self-discharge rate; calculating a capacity deterioration rate of each charge cycle of the battery; and correcting the FCC using the calculated self-discharge rate and the calculated capacity deterioration rate to estimate the SOC of the battery, wherein the FCC is updated after the battery is fully charged; characterized in that: the step S5 comprises correcting the FCC according to the following expression: FCC NEW = Calculated FCC * Cell self-discharge Rate * Capacity Deterioration by Cycle Rate, where Cell self-discharge Rate and Capacity Deterioration by Cycle Rate represent the self-discharge rate and the capacity deterioration rate, respectively; the self-discharge rate is calculated according to the following expression: Self-discharge Rate = 1 − Y 1 * t _ y 1 + Y 2 * t _ y 2 + Y 3 * t _ y 3 + Y 4 * t _ y 4 * Number of parallel cells/Design Capacity, where Y1, Y2, Y3 and Y4 denote respective self-discharge rate values of four state areas, into which states of the battery are divided based upon a specific voltage and a specific temperature, t_y1, t_y2, t_y3 and t_y4 denote respective discharge times in the four state areas, and Y1, Y2, Y3 and Y4 are set with reference to the specific voltage and the specific temperature; and the capacity deterioration rate is calculated according to the following expression: Capacity Deterioration Rate = 1 − C 1 * cycle 1 + C 2 * cycle 2 + C 3 * cycle 3 + C 4 * cycle 4 * Number of parallel cells / Design Capacity, where C1, C2, C3 and C4 denote respective capacity deterioration rate values of four state areas, into which states of the battery are divided based upon a specific period and a specific temperature, cycle 1, cycle 2, cycle 3 and cycle 4 denote the respective numbers of charge cycles in the four state areas, and C1, C2, C3 and C4 are set with reference to the specific period and the specific temperature, in which the specific period and the specific temperature are determined within a range of 50 to 150 days and a range of 30°C to 50°C. measuring voltage and current of the battery; calculating the FCC using a voltage change and a current integral of the battery during a specific time; estimating a time remaining until the battery is fully discharged using the calculated FCC and the measured voltage and current to calculate a self-discharge rate; calculating a capacity deterioration rate of each charge cycle of the battery; and correcting the FCC using the calculated self-discharge rate and the calculated capacity deterioration rate to estimate the SOC of the battery, wherein the FCC is updated after the battery is fully charged; the step S5 comprises correcting the FCC according to the following expression: FCC NEW = Calculated FCC * Cell self-discharge Rate * Capacity Deterioration by Cycle Rate, where Cell self-discharge Rate and Capacity Deterioration by Cycle Rate represent the self-discharge rate and the capacity deterioration rate, respectively; the self-discharge rate is calculated according to the following expression: Self-discharge Rate = 1 − Y 1 * t _ y 1 + Y 2 * t _ y 2 + Y 3 * t _ y 3 + Y 4 * t _ y 4 * Number of parallel cells/Design Capacity, where Y1, Y2, Y3 and Y4 denote respective self-discharge rate values of four state areas, into which states of the battery are divided based upon a specific voltage and a specific temperature, t_y1, t_y2, t_y3 and t_y4 denote respective discharge times in the four state areas, and Y1, Y2, Y3 and Y4 are set with reference to the specific voltage and the specific temperature; and the capacity deterioration rate is calculated according to the following expression: Capacity Deterioration Rate = 1 − C 1 * cycle 1 + C 2 * cycle 2 + C 3 * cycle 3 + C 4 * cycle 4 * Number of parallel cells / Design Capacity, where C1, C2, C3 and C4 denote respective capacity deterioration rate values of four state areas, into which states of the battery are divided based upon a specific period and a specific temperature, cycle 1, cycle 2, cycle 3 and cycle 4 denote the respective numbers of charge cycles in the four state areas, and C1, C2, C3 and C4 are set with reference to the specific period and the specific temperature, in which the specific period and the specific temperature are determined within a range of 50 to 150 days and a range of 30°C to 50°C.