This study proposes a blue-green light-emitting diode light source system for jaundice phototherapy instrument. Based on the process of light transmission through skin and tissues and the process of conversion between bilirubin and phosgene, a light spectrum with a higher matching degree to the target spectrum is established via the spectral matching method. In addition, the light source array is designed and simulated, followed by the fabrication and illumination test of the corresponding light source system. The results indicate that the system achieves an average illumination of 32.9 μW·cm -2·nm -1 with 81% uniformity. The uniformity is further improved by adding a Fresnel lens array to the light source system. When the ring distance of the Fresnel lens is 1 mm and the distance from the lens to the light source is 1 cm, the uniformity is increased to 85% and the illuminance is 31 μW·cm -2·nm -1 , which are in accordance with the design requirements.