A total of 34 body condition and laying performance in laying period consistent ShanMa ducks，were randomly divided into two groups to study the effect of feeding exogenous melatonin on the perform-ance of egg-laying ducks． The test group was given 3 mg melatonin of each duck on each day，and thecontrol group did not add． The two groups all maintained light in 24 h，and the test period lasted 7weeks． During the period that feed intake，egg production and serum hormone levels of egg duck weremeasured． The results showed that melatonin reduced the egg laying performance of duck，and increasedthe blood melatonin levels，decreased the level of estradiol，luteinizing hormone and progesterone com-pared with control group，but the difference was not significant ( P ＞0. 05) ，the effect of pheromone onthe reproductive hormone levels of the eggs was not significant．