The disclosure provides a light-emitting device. The light-emitting device comprises: a substrate having a first patterned unit; and a light-emitting stack on the substrate and having an active layer with a first surface; wherein the first patterned unit, protruding in a direction from the substrate to the light-emitting stack, has side surfaces abutting with each other and substantially non-parallel to the first surface in cross-sectional view, and has a non-polygon shape in top view.