A method for preventing fake charging of an electronic apparatus is provided. The method includes: providing a power management table for setting function units for each power range; activating a fake charging preventing function according to a predetermined condition or an activating operation of users; detecting power of the electronic apparatus every a first predetermined time interval; determining a current power range the detected power falls into; determining whether the current power range is changed; beginning to time when the current power range is changed; activating function units which are disabled and whose power range is the current power range when the timing reaches a second predetermined time interval and the detected power is still in the current power range.