Abstract: The metabolism of catecholamine and tyrosine was studied by repeated exposure to psychological stress in rats,as well as the study of dietary tyrosine supplementation in rats during repeated psychological stress.It was found that on exposure day 1、3 and 7,the values of urinary catecholamine in the stressed group(S group)and in the stressed group with tyrosine supplementation(ST group)were higher than those in control group(C group)(P0 05)respectively.The tyrosine concentrations of plasma and brain homogenate in ST group were higher than those in S group and C group(P0 01)on day 14 respectively.On day 7 the value of the open field test in S group was lower than that in C group(P0 05),but tyrosine supplementation tended to counteract the performance decrement in the ST group.