The research about preliminary study absorption spectrum of Breadfruit leaves extract from kupang city has been done. This research aims to determine the absorption range, the absorption coefficient, the energy gap and the refractive index of Breadfruit leaves extract. Breadfruit leaves powder was extracted by maseration method, then it was evaporated by evaporator and further diluted using ethanol and then characterized using UV-Vis spectrophotometer to abtain absorption spectrum of Breadfruit leaves extract. Based on absorption spectrum data analysis, the absorption range occurs of wavelength 200 nm to 500 nm, the absorption coefficient is 105,9567 m-1, the energy gap value is 3,03 eV and the refractive index value is 1,75. Keywords: Breadfruit leaf, Absorption Spectrum, Absorption Coefficient, Energy Gap, and Refractive Index Value.