The disclosure provides a backlight module applied to a liquid crystal display device. The backlight module includes: a control circuit for outputting a driving signal according to an analog adjustment signal or a digital adjustment signal; a driving circuit for outputting a lamp voltage according to the driving signal; a fluorescent lamp set, including a plurality of lamps, for receiving the lamp voltage and thereby generating a lamp current; a lamp feedback circuit c for outputting a feedback signal according to the lamp voltage; and a dynamic protection circuit, for dynamically adjusting a protection command signal according to the analog dimming signal or the digital dimming signal, comparing the protection command signal and the feedback signal and thereby outputting a comparing result signal to the control circuit.