Disclosed is an LED backlight driving circuit and method for detecting failure thereof. A driving chip of the circuit, on the one hand, is electrically connected to a control end of a booster unit so as to transmit a gate control signal to the booster unit, for regulating a driving voltage supplied by a power supply unit to an LED light strip through the booster unit, and on the other, is electrically connected between an output end of a detection unit and a negative end of the LED light strip, forming a current path of the LED light strip. When the detection unit outputs a variable testing voltage, the driving chip controls a current flowing through the LED light strip so that the current changes with the testing voltage, and judges whether to cut off its electrical connection to the LED light strip based on a comparison of a voltage on the negative end of the LED light strip and a predetermined threshold voltage.