An apparatus for charging a battery, characterizied by comprising: a constant current circuit (403, 603), a constant voltage circuit (404, 604) and a control circuit (405, 607); wherein the control circuit (405, 607) is adapted to control the constant current circuit (403, 603) to perform constant current charging to the battery (402, 602); after a battery voltage during the constant current charging reaches a preset charging limited voltage, control the constant voltage circuit (404, 604) to perform constant voltage charging to the battery (402, 602); after a charging current during the constant voltage charging becomes smaller than or equal to a predetermined threshold, control the battery (402, 602) to be charged by pulse charging until an open circuit voltage of the battery (402, 602) is larger than or equal to a preset voltage threshold; the apparatus further comprising a clock circuit; wherein the control circuit (405, 607) further comprises: a first unit, adapted to stop the charging to the battery (402, 602) and trigger the clock circuit to start timing; a second unit, adapted to, when a timing period reaches a preset off time, clear the timing of the clock circuit and determine whether an open circuit voltage of the battery (402, 602) is larger than or equal to the preset voltage; if the open circuit voltage is larger than or equal to the preset voltage, terminate the charging; otherwise, control the constant voltage circuit (404, 604) to perform the constant voltage charging to the battery (402, 602) and meanwhile trigger the clock circuit to start timing, and when a charging time reaches a predetermined pulse-charging-on time, clear the timing of the clock circuit, and trigger the first unit to stop charging the battery (402, 602) and to trigger the clock circuit to start timing. a constant current circuit (403, 603), a constant voltage circuit (404, 604) and a control circuit (405, 607); wherein the control circuit (405, 607) is adapted to control the constant current circuit (403, 603) to perform constant current charging to the battery (402, 602); after a battery voltage during the constant current charging reaches a preset charging limited voltage, control the constant voltage circuit (404, 604) to perform constant voltage charging to the battery (402, 602); after a charging current during the constant voltage charging becomes smaller than or equal to a predetermined threshold, control the battery (402, 602) to be charged by pulse charging until an open circuit voltage of the battery (402, 602) is larger than or equal to a preset voltage threshold; control the constant current circuit (403, 603) to perform constant current charging to the battery (402, 602); after a battery voltage during the constant current charging reaches a preset charging limited voltage, control the constant voltage circuit (404, 604) to perform constant voltage charging to the battery (402, 602); after a charging current during the constant voltage charging becomes smaller than or equal to a predetermined threshold, control the battery (402, 602) to be charged by pulse charging until an open circuit voltage of the battery (402, 602) is larger than or equal to a preset voltage threshold; the apparatus further comprising a clock circuit; wherein the control circuit (405, 607) further comprises: a first unit, adapted to stop the charging to the battery (402, 602) and trigger the clock circuit to start timing; a second unit, adapted to, when a timing period reaches a preset off time, clear the timing of the clock circuit and determine whether an open circuit voltage of the battery (402, 602) is larger than or equal to the preset voltage; if the open circuit voltage is larger than or equal to the preset voltage, terminate the charging; otherwise, control the constant voltage circuit (404, 604) to perform the constant voltage charging to the battery (402, 602) and meanwhile trigger the clock circuit to start timing, and when a charging time reaches a predetermined pulse-charging-on time, clear the timing of the clock circuit, and trigger the first unit to stop charging the battery (402, 602) and to trigger the clock circuit to start timing. a first unit, adapted to stop the charging to the battery (402, 602) and trigger the clock circuit to start timing; a second unit, adapted to, when a timing period reaches a preset off time, clear the timing of the clock circuit and determine whether an open circuit voltage of the battery (402, 602) is larger than or equal to the preset voltage; if the open circuit voltage is larger than or equal to the preset voltage, terminate the charging; otherwise, control the constant voltage circuit (404, 604) to perform the constant voltage charging to the battery (402, 602) and meanwhile trigger the clock circuit to start timing, and when a charging time reaches a predetermined pulse-charging-on time, clear the timing of the clock circuit, and trigger the first unit to stop charging the battery (402, 602) and to trigger the clock circuit to start timing.