In order to investigate the effect of light on flower aroma of Oncidium Sw.， flower aromatic components and relative contents of Oncidium Sharry Baby ‘Sweet Fragrance’ at full flowering stage under illumination intensity of 1 510， 2 170， and 3 240 lx conditions were detected and compared by GC-MS technology. The results show that under illumination intensity of 1 510, 2 170, and 3 240 lx conditions， there are obvious differences in flower aromatic components and relative contents， but relative content of ocimene is the highest. There are 36， 43， and 35 kinds of flower aromatic components under illumination intensity of 1 510， 2 170， and 3 240 lx conditions， respectively； in addition， relative contents of most flower aromatic components are the highest under illumination intensity of 2 170 lx condition， but are the lowest under illumination intensity of 1 510 lx condition. Sensory evaluation result shows that flower aroma concentration index is relatively small under no light and weak light conditions， but relatively large under strong light condition. It is suggested that there is an obvious effect of light on flower aroma of Oncidium Sharry Baby ‘Sweet Fragrance’， in which， number and relative contents of flower aromatic components are basically the highest under illumination intensity of 2 170 lx condition.