LED illumination device and lamp unit thereof

An LED illumination device includes a lampshade, and a plurality of lamp units mounted on the lampshade. Each lamp unit includes a light-emitting module having a plurality of light sources and a heat sink arranged above the light-emitting module. The heat sink includes an elongated base and a plurality of fins on the base. The base has an outer convex surface formed at a top side thereof and an opposite inner concave surface formed at a bottom side thereof. The fins extend outwardly from the convex surface of the base. The concave surface defines an elongated recess extending along an axial direction of the base. Two opposite free ends of the base are spaced from each other and cooperatively define a light emitting window below the concave surface. The light sources are received in the recess and thermally attached to the concave surface.