The invention discloses a white light LED light source, a backlight module and a liquid-crystal display device. The white light LED light source comprises a lamp bar provided with a plurality of LED lamps; each LED lamp is provided with a chip and a fluorescence module, wherein the chip emits first color light, and the fluorescence module is excited by the first color light to emit second color light. The lamp bar is further provided with a plurality of laser devices, and third color light is emitted by the laser devices and mixed with the light emitted by the LED lamps to form white light. According to the white light LED light source, the laser devices are used for replacing fluorescent powder which can emit the third color light after being excited by the chip in the fluorescence module in the prior art, the third color light in the light emitted by the white light LED light source is directly provided by the laser devices, and the color purity of the third color light in the light emitted by the white light LED light source is improved, so that the color gamut of the liquid-crystal display device with the white light LED light source is widened, and then the display effect of the display device is improved.