An LED lamp structure includes a heat sink and a base. The heat sink includes a first receiving cavity, a second receiving cavity opposite to the first receiving cavity and a partition. A light board having LED modules is mounted on the partition. The partition defines two first threaded through holes therein. The base has two positioning protrusions engaging in two positioning grooves of the heat sink. Thus, second screw holes of two screw pillars of the base are aligned at the first screw holes of the partition of the heat sink. Screws are used to threadedly engage in the first screw holes, the second screw holes and third screw holes in the light board to thereby assemble the heat sink, the base and the light board together.