The present invention provides a voltage boost driving circuit for LED backlight, which includes a first power input port, a second power input port, an LED light bar, a positive boost circuit, a negative boost circuit, and a luminance controlling circuit configured for controlling the luminance of the LED light bar; the first and second power input ports are respectively connected to the positive and negative poles of an external power supply; the positive boost circuit is connected between the first power input port and the positive pole of the LED light bar; the second power input port is connected to the ground; the negative boost circuit is connected to the positive boost circuit via the luminance controlling circuit, an output port of the negative boost circuit is connected to the negative pole of the LED light bar. An LCD device is further provided.