This study focused on evaluating the effects of feeding frequency on growth performance of Litopenaeus vannamei fed diet with crystalline methionine.The growth experiment was conducted to test three dietary treatments including fish meal(32%)as positive control,fish meal(16%)with methionine deficiency as negative control,and fish meal(16%)with crystalline L-methionine(MET)as the test diet.Feeding frequency trial was conducted in order to explore the difference in absorption of crystalline methionine and amino acid from intact protein(positive control and negative control).Shrimp were fed MET dietary in feeding frequency 2(7:00 and 21:00),4(7:00,12:00,18:00 and 21:00),and 6 times-day(7:00,9:30,12:00,15:00,18:00 and 21:00),the positive control and negative control were fed 4 times per day only.Each treatment was randomly assigned to triplicate groups of 30 shrimps(initial weight 1.27?0.01 g)per aquarium.Shrimp were maintained in aquaria for 5 weeks at water temperature that ranged from 29 to 30 ℃.The results showed that shrimp fed MET diet 6 times per day had no difference in weight gain with positive control(P>0.05).Crude protein contents of shrimp body of shrimp fed MET 6 times per day were significantly higher than that 4 times per day(P<0.05).Total protease activities of shrimp increased with feeding frequency increased,which fed MET 4 times per day and 6 times per day had no difference with positive control(P>0.05).These results indicate that the shrimp fed low fishmeal diet supplemented with methionine had better weight gain,body protein deposition and total protease activities with feeding frequency from 4 to 6 times per day.Increased feeding frequency could improve utilization of free amino acid.