An exemplary LED driving method is adapted for driving multiple LED strings. Each of the LED strings includes single one LED or multiple LEDs connected in series. In particular, the LED driving method includes steps of: obtaining an initial value of a duty-on period of a driving current in a frequency period to thereby acquire a target accumulative luminosity in the initial value of the duty-on period for each of the LED strings; and prolonging the duty-on period of the driving current in the frequency period and assuring an accumulative luminosity in the prolonged duty-on period to be substantially equal to the target accumulative luminosity for each of the LED strings, when the maximum one of the initial values of the duty-on periods of the driving currents in the frequency period for the LED strings is shorter than the frequency period.