Abstract: Effects of different temperature treatments on ‘Sanyuehong’ litchi （Litchi chinensis Sonn.） during floral induction stage and morphological differentiation stage were studied using growth chambers. The results showed that trees treated with low temperatures（15 ℃/8 ℃，day 12 h/ night 12 h），or medium low temperatures（18 ℃/13 ℃）in the induction stage then high temperatures（28 ℃/23 ℃）in the morphological differentiation stage had a low percentage of terminal branches flowering. High temperatures in the morphological differentiation stage decreased the number of flowers per panicle and fresh weight of female flower. It was suggested that 18 ℃/13 ℃ treatment in the induction stage and 15 ℃/8 ℃ treatment in the morphological differentiation stage would be beneficial for flowering. Compared with those in medium and low temperatures，floral buds in high temperatures had a lower flowering in different temperature treatments and phytohormones as well as LcLFY expression was content of zeatin（ZRs）and a higher content of auxin. The litchi LFY homologue（LcLFY）expression in floral buds in the high temperatures was weaker than that in low temperatures. The relationship between flowering indifferent temperature treatments and phytohormones as well as LcLFY expression was discussed.

Key words: litchi, temperature, flowering