A LED lighting device includes a LED module and a diaphanous cover. The LED module includes a circuit board and a plurality of LED lamps. Each of the LED lamps includes a lens unit and a LED package. The lens unit includes a lens body, a frame and at least one pillar. The frame extends from a periphery of the lens body and is mounted on bottom of the circuit board. The pillar extends downward from a bottom surface of the frame. The LED package is mounted in the frame, and has a light emitting surface facing the lens body and a back surface joined to the bottom of the circuit board. The diaphanous cover abuts upward against all distal ends of the pillars of the LED lamps and is secured on the circuit board of the LED module.