The present disclosure proposes a light-emitting device and a backlight module thereof. The light-emitting elements includes a substrate, a plurality of light-emitting elements, a light guide layer, a plurality of first light adjustment patterns, and a plurality of second light adjustment patterns. The light-emitting elements are disposed on the substrate. The light guide layer covers the substrate and the light-emitting elements. The first light adjustment patterns are disposed over or embedded within the light guide layer, and each of the first light adjustment patterns is located above each of the light-emitting elements, respectively. The second light adjustment patterns are disposed on or embedded in the light guide layer, and the second light adjustment patterns surround the corresponding first light adjustment patterns, respectively. The first light adjustment patterns and second light adjustment patterns have a refractive index smaller than that of the light guide layer.