The present disclosure provides a backlight driving circuit and a liquid crystal display device. The backlight driving circuit of the present disclosure adds a light emitting control module to control a light emitting device to turn on or off, thereby controlling a backlight to turn on or off, realizing a function of black insertion frame by frame of the backlight of the liquid crystal display device, satisfying a BFI function requirement. In addition, it improves product quality. In addition, the liquid crystal display device of the present disclosure lights up the backlight after a deflection of a liquid crystal layer is stabilized and displays normally, and therefore, a problem of trailing when displaying images can be decreased.