Abstract: Solutions of active oxygen scavengers were sprayed on the late-maturing longan trees to examine the effect on quality of the fruits. Seven chemical agents, including sodium benzoate, mannitol, propyl gallate, acetyl salicylic acid, ascorbic acid, L-cysteine and vitamin E, in water solutions at a concentrations of 1 g·L^-1were used for the experiment. A double distilled water was applied as control. It appeared that the solutions containing these active oxygen scavengers, especially ascorbic acid and propyl gallate, could decrease the lipid peroxidation in the membrane of pericarp, inhibit formation of MDA in the pericarp, delay and reduce the autolysis of fruitflesh, as well as maintain the level of soluble solidcontent in the fruits.