A light emitting device, comprising: a first light emitting diode array (310, 710, 810), including blue LEDs, for emitting a first light; a second LED array (320, 720, 820), including green LEDs and yellow phosphor LEDs, or green LEDs and green phosphor LEDs, for emitting a second light, wherein at least a part of the second light is incident in a wavelength-based light combination device (340, 740, 840); a third LED array (330, 730, 830), including at least one of red LEDs and red phosphor LEDs, and at least one of amber LEDs and amber phosphor LEDs, for emitting a third light; a wavelength-based light combination device (340, 740, 840) which includes a first filter plate (341, 741) and a second filter plate (342, 742), wherein the first filter plate (341, 741) has an optical property that reflects light with wavelengths below or equal to λ 1 and transmits light with wavelengths above λ 1, the second filter plate (342, 742) has an optical property that transmits light with wavelengths below or equal to λ 2 and reflects light with wavelengths above λ 2, where 470 nm ≤ λ 1 ≤ 500 nm and 560 nm ≤ λ 2 ≤ 590 nm; wherein the first filter plate (341, 741) receives the first light and the second light which are incident on its different sides, and outputs a reflected part of the first light and a transmitted part of the second light along a first direction; wherein the second filter plate (342, 742) receives the third light and the second light which are incident on its different sides, and outputs a transmitted part of the second light and a reflected part of the third light along the first direction, wherein the first direction is along the direction of the optical axis of the second LED array (320, 720, 820), wherein the wavelength-based light combination (340, 840) device is X-shaped filter plates, characterized in that the light emitting device further includes a first reflecting plate and second reflecting plate disposed respectively on two sides of the wavelength-based light combination device (340, 740, 840), wherein the first reflecting plate and the second reflecting plate are parallel to a plane defined by optical axes of the first LED array (310, 710, 810), the second LED array (320, 720, 820) and the third LED array (330, 730, 830), for reflecting lights incident on the first and second reflecting plates (380, 390). a first light emitting diode array (310, 710, 810), including blue LEDs, for emitting a first light; a second LED array (320, 720, 820), including green LEDs and yellow phosphor LEDs, or green LEDs and green phosphor LEDs, for emitting a second light, wherein at least a part of the second light is incident in a wavelength-based light combination device (340, 740, 840); a third LED array (330, 730, 830), including at least one of red LEDs and red phosphor LEDs, and at least one of amber LEDs and amber phosphor LEDs, for emitting a third light; a wavelength-based light combination device (340, 740, 840) which includes a first filter plate (341, 741) and a second filter plate (342, 742), wherein the first filter plate (341, 741) has an optical property that reflects light with wavelengths below or equal to λ 1 and transmits light with wavelengths above λ 1, the second filter plate (342, 742) has an optical property that transmits light with wavelengths below or equal to λ 2 and reflects light with wavelengths above λ 2, where 470 nm ≤ λ 1 ≤ 500 nm and 560 nm ≤ λ 2 ≤ 590 nm; wherein the first filter plate (341, 741) receives the first light and the second light which are incident on its different sides, and outputs a reflected part of the first light and a transmitted part of the second light along a first direction; wherein the second filter plate (342, 742) receives the third light and the second light which are incident on its different sides, and outputs a transmitted part of the second light and a reflected part of the third light along the first direction, wherein the first direction is along the direction of the optical axis of the second LED array (320, 720, 820), wherein the wavelength-based light combination (340, 840) device is X-shaped filter plates, characterized in that the light emitting device further includes a first reflecting plate and second reflecting plate disposed respectively on two sides of the wavelength-based light combination device (340, 740, 840), wherein the first reflecting plate and the second reflecting plate are parallel to a plane defined by optical axes of the first LED array (310, 710, 810), the second LED array (320, 720, 820) and the third LED array (330, 730, 830), for reflecting lights incident on the first and second reflecting plates (380, 390).