The invention discloses a preparation method of a long-life storage battery and the storage battery. The preparation method comprises the following steps: (1) adding acid into an assembled storage battery and then connecting the assembled storage battery into a charging circuit; (2) performing constant voltage control on the storage battery to form an alpha-PbO2 transition layer at the interface of the positive grid and the positive active material; and (3) carrying out container formation on the storage battery. The invention discloses the preparation method of the long-life storage battery.After acid treatment, the battery is immediately subjected to constant voltage control without standing; at the moment, an alkaline environment is formed between a positive grid and the active substance, a compact transition layer is formed between the active substance and the grid, a battery of the transition layer is formed, the voltage can be obviously reduced at the initial stage of formation,water decomposition cannot be generated at the early stage, the transition layer is kept in a good state, and the service life of the battery treated by the method can be obviously prolonged.