Abstract: A light-emitting device capable of producing white light includes at least two types of LED elements and at least one encapsulant material. Each of the LED elements has an epitaxial light-emitting layer grown on a substrate; and the epitaxial light-emitting layers for the LED elements are the same series of AlGaInN materials having emission wavelengths in a region from violet to green light and different from one another by at least 30 nm. The encapsulant material encapsulates the LED elements and contains an adequate amount of fluorescent powder, which can be excited to emit complementary color lights to mix with color lights from the LED elements to produce bluish, yellowish, greenish or reddish white light. At least two types of the white light-emitting devices can be differently arrayed in a module or a system to produce a white light with high color-rendering index and good light mixing effect.