The present invention discloses a LED backlight driving method, a LCD device and a LED backlight driving circuit, wherein the LED backlight driving method comprises the following steps: regulating the current of each LED string so that the voltages of all LED strings are equal; and regulating the duty cycle of the current of the corresponding LED string so that the effective value of the current of each LED string meets the preset requirement of brightness. The present invention solves the problem of consumption caused by voltage difference by regulating the current through the current regulation module to ensure that the voltages of all the LED strings are equal, and ensures the brightness consistency by regulating the duty cycle through the duty-cycle regulation module so that the effective value of the currents of all the LED strings are equal.