A color temperature adjusting method of solid state light emitting device, including steps: providing a main light source which emits main light of a first color temperature; providing an adjusting light source, wherein the adjusting light source comprises a red light source, a green light source and a blue light source; and adjusting currents applied to the adjusting light sources to obtain an adjusting light, wherein the adjusting light mixes with the main light of the main light source to obtain an outgoing light of a second color temperature. The second color temperature is different from the first color temperature. The outgoing light has a chromaticity coordinate at a Plank's curve on a CIE 1931 chromaticity coordinates chart.