Abstract: Light emitting diode（LED）was applied to accurately modulate red light（630 ± 20）nm，light intensity and photoperiod. The effects of photoperiod under red LED on the growth and quality of sunflower sprouts were studied. The results indicated that the extended photoperiod from 0 to 12 h · d-1 could significantly inhibit the elongation of hypocotyls，expand the cotyledon area，and the extended photoperiod from 0 to 16 h · d-1 could significantly increase the content of chlorophyll and carotenoid. Under the treatment of 16 h · d-1 photoperiod，the fresh mass and the starch content were improved evidently. While the extended photoperiod under red LED promoted the content of vitamin C，it still decreased the content of free amino acid，restrained the activity of SOD and CAT. Overall，as compared with other photoperiod，16 h · d-1 photoperiod was more beneficial to the growth and some qualities of sunflower sprouts.

Key words: Helianthus annuus L, sprout, photoperiod, light emitting diode（LED）, growth, quality