The present invention provides a method for reasonably adjusting an end-of-discharge voltage of a lithium battery with attenuation of a battery life. The method includes: acquiring an end-of-charge voltage, an end-of-discharge voltage and a rated capacity based on a basic parameter table for a lithium battery, then setting a safety end-of-charge voltage and a safety end-of-discharge voltage to obtain an initial safety discharge capacity, and finally setting a preset discharge capacity of the battery; using an Ampere-hour integration method to estimate a discharged power, taking the preset discharge capacity as a discharge standard, and stopping discharge when the discharged power reaches the preset discharge capacity; and the safety discharge capacity being gradually less than the preset discharge capacity within a battery life cycle, and the battery stopping discharge when the voltage reaches the safety end-of-discharge voltage. By controlling the discharge capacity to be unchanged, the present invention ensures stably outputting power in the case that the battery capacity attenuates, so that a user feels that the endurance mileage of an electric vehicle is stably unchanged within a certain period. The method has the characteristics of simple adjusting control method and convenience in commercialization.