In order to improve bilirubin degradation effect and neonatal jaundice phototherapy efficiency, a light source of light-emitting diode (LED)-based neonatal jaundice therapeutic device (NJTD) is designed and developed. The most efficient absorption spectrum of standard bilirubin in vitro tested by the experiment is regarded as the target spectrum of NJTD light source. The commercial available monochromatic LEDs with different peak wavelengths and full width at half maximum (FWHM) are used as matching sources, and the simple genetic algorithm (SGA) is introduced as the spectral matching method. The spectral matching design is realized for the light source of the novel NJTD, and subsequently, the light sample model is developed, the corresponding spectrum is measured and the effect is analyzed finally. Results show that the fitted spectrum is in close proximity to the target spectrum with 97.62% matching degree, the spectrum of the light sample model developed is very comparable to the target spectrum with 93.08% matching degree，monochrome LEDs with narrow bandwidth can match the required target spectrum perfectly. The spectral matching degree is higher, which provides research foundation for the selection of LED-based NJTD light source.