This research was carried out in Antoniadis Garden, Alexandria city, Egypt, on trees of fourteen genera belong to family fabaceae, to study the differences on their leaves spectral  properties, using some vegetation indices "NDVI, SR, IR/R, IR/G, RE, REP and DN". Also, spectral reflectance curve of each tree species and for each and both leaf surface was drawn to examine the ability of spectral measurements and vegetation indices to differentiate among tree species. Moreover, leaves content of total chlorophyll was determined and it's correlation to studied indices was examined. Results showed that all studied indices can successfully differentiate among trees species and showed a highly significant differences between species. Moreover, spectral curve of each plant species were obviously separated for each and both leaf surface. It is manifested that Green and NIR regions are clearly separated between spectral curves of leaves according to their color, thickness and internal structure, so this electro-magnetic radiation of light can be used successfully to classify plant species. Also, a highly correlation was found between total chlorophyll content and studied vegetation indices