A light-emitting device includes a carrier with a first surface and a second surface opposite to the first surface; and a light-emitting unit disposed on the first surface and configured to emit a light toward but not passing through the first surface. When emitting the light, the light-emitting device has a first light intensity above the first surface, and a second light intensity under the second surface, a ratio of the first light intensity to the second light intensity is in a range of 2˜9.