An LED backlight driving circuit with a voltage regulating unit is provided. The LED backlight driving circuit includes a power supply unit, an LED string, an ADC voltage detection circuit, and a driving controller; the ADC voltage detection circuit is used to detect a voltage value Vled of a negative terminal of a LED string, and the ADC voltage detection circuit includes an ADC sampling module that converts the measured voltage value Vled at the negative terminal of the LED string into a voltage numerical code; for the numerical code of the negative terminal voltage value Vled measured by the ADC sampling module, a first threshold V1 and a second threshold V2 are set.