Abstract: The effect of differernt LED light quality treatment on photosynthesis and chlorophyll fluorescence parameters of overwintering pepper in greenhouse was studied.The results showed that the photosynthesis rate， stomatal conductance， transpiration rate， intercellular CO2 concentration and Fv′/Fm′， qN， ΦPSII， ETR， qP had significant impact under differernt LED light quality and differernt supplemental time on pepper leaves. Treated with short time （6 hours and 8 hours）， the photosynthetic rate， intercellular CO2 concentration， ΦPSII and ETR of pepper were significantly improved under RB light and B light， and supplementary lighting for 6 hours was better than 8 hours. Treated with long time （10 hours）， Fv′/Fm was significantly improved under RB light， but more heat was disspated under W light and RB73 light. Treatment under RB83 light for 6 h and 8 h can significantly improve the photosynthesis of pepper， therefore the two treatments can be used as supplemental light in greenhouse production of overwintering pepper.

Key words: pepper, LED, photosynthesis, chlorophyll fluorescence parameters