A light-emitting device includes a light-emitting stack and a distributed Bragg reflection structure formed on one side light-emitting stack. The distributed Bragg reflection structure includes a first film stack, a second film stack and a conversion layer between the first and the second film stacks; wherein the first film stack includes a plurality of first dielectric-layer pairs consecutively arranged, the second film stack includes a plurality of second dielectric-layer pairs consecutively arranged, each of the first dielectric-layer pairs and each of the second dielectric-layer pairs respectively includes a first dielectric layer having an optical thickness and a second dielectric layer having an optical thickness; wherein the second dielectric layer has a refractive index higher than that of the first dielectric layer; wherein in each of the first dielectric-layer pairs of the first film stack, the optical thickness of the first dielectric layer to the optical thickness of the second dielectric layer has a first ratio, and in each of the second dielectric-layer pairs of the second film stack, the optical thickness of the first dielectric layer to the optical thickness of the second dielectric layer has a second ratio; wherein the first ratio is greater than the second ratio; wherein the conversion layer has an optical thickness ranging between that of the first dielectric layer of one of the first dielectric-layer pairs of the first film stack and that of the first dielectric layer of one of the second dielectric-layer pairs of the second film stack.