This study was conducted to investigate the effect of ultraviolet light (UV-B) on plant growth and petal antioxidants of edible flower pansy (Viola × wittrochiana ‘Rose’ and ‘Yellow’, V. cornuta ‘Purple’). The plants were grown under white LED of 100 μmol·m-2·s-1 PPFD and treated by UV-B of 10, 20 and 30 minutes per day: UVB-10, UVB-20, and UVB-30 respectively. The plant growth was significantly inhibited as longer UV-B radiation exposure, even ‘Rose’ could not f lower under UVB-30. NPQ increase was observed in all cultivars with longer UV-B irradiation exposure. Also, anthocyanin in ‘purple’ and ‘Rose’ or carotenoid in ‘Yellow’ increased in the petals as longer UV-B radiation exposure. Unexpectedly the contents of total phenol and DPPH did not show the significance in UV-B treatments. In conclusion, the applicable UVB exposure to edible pansy in order to more accumulate antioxidants in petals would be in 20 minutes per day.