The changes of lycopene content during ripening and senescence of tomato fruit and the relationship between ethylene glycol-bis (EGTA, Ca 2+ chelator), verapamil (Vp, Ca 2+ channel blockers), trifluoperazine (TFP), chloropromaize (CPZ) (CaM antagonism) and ethylene-induced increase in lycopene content in tomato fruit were investigated. Lycopene content accumulated obviously during ripening and senescence of tomato fruit after harvest at pink stage. Low temperature inhibited but ethylene enhanced the lycopene content. Meanwhile, ethylene also promoted calmodulin (CaM) content in tomato fruit, which was related to the concentration of ethylene. When EGTA, Vp, TFP and CPZ with ethylene were used to treat tomato fruit, ethylene-induced increase in lycopene content could be reversed, indicating that blocking Ca 2+ channel in plasma membrane or chelating extracellular Ca 2+ or inhibiting the activity of CaM could decrease the action of ethylene, and suggesting that Ca 2+-CaM messenger system may be involved in lycopene increase induced by ethylene. The changes of lycopene content during ripening and senescence of tomato fruit and the relationship between ethylene glycol-bis (EGTA, Ca 2+ chelator), verapamil (Vp, Ca 2+ channel blockers), trifluoperazine (TFP), chloropromaize (CPZ) CaM antagonism) and ethylene-induced increase in lycopene content in tomato fruit were investigated. Lycopene content breaking up during ripening and senescence of tomato fruit after harvest at pink stage. Low temperature inhibited but ethylene enhanced the lycopene content. Meanwhile, ethylene also promoted calmodulin When EGTA, Vp, TFP and CPZ with ethylene were used to treat tomato fruit, ethylene-induced increase in lycopene content could be reversed, indicating that blocking Ca 2 + channel in plasma membrane or chelating extracellular Ca 2+ or inhibiting the activity of CaM could decrease the action of ethylene, and suggesting that Ca 2 + -CaM m essenger system may be involved in lycopene increase induced by ethylene.