An LED illumination device includes a light source and a heat sink. The heat sink includes an elongated base and a plurality of fins extending from the base. The base has a heat-absorbing surface and an opposite heat-spreading surface. The fins extend upwardly from the heat-spreading surface. The light source is attached to the heat-absorbing surface, whereby heat generated by the light source is removed by the heat sink. The heat-absorbing surface is one of a convex surface and a concave surface, whereby light emitted from the light source is diverged or converged towards objects.