Objective To observe modulatory effects of electroacupuncture (EA) on hypothalamus-pituitary adrenal (HPA) axis, thymus-exponent (TE), γ-IFN and interleukin-2 (IL-2) in rats with exercise-induced immunosuppression. Methods Forty-three SD rats were randomly, by using digits, divided into three groups: group A, B and C. Group A (n=10) was taken as a control group. Rats in group B (n=17) accepted intense swimming exercise for 150 min each time, 6 times each week for 8 weeks. Rats in group C (n=16) accepted EA intervention following each swimming since the second week of swimming exercise with the same duration and times as those in group B. The indices reflecting functional states of the HPA axis such as hypothalamic corticotropin releasing hormone (CRH), plasma adrenocorticotropic hormone (ACTH), corticosterone (CORT) etc. and changes in TE, serum γ-IFN, and IL-2 were determined. Results (1) Compared with group A, the values of ACTH and CORT in group B significantly increased (P〈0.01, P〈0.05), but no significant differences were found in group C (both P〉0.05) though they were somewhat elevated. Compared with group A, CRH values increased by 85.14% in group B and decreased by 64.09% in group C, respectively, but both differences were without statistical significance (both P〉0.05). Serum IL-2, γ-IFN and TE values in group B were significantly lower than those in group A(P〈0.05, P〈0.01 ), among which γ-IFN decreased by 32.19%. The values of IL-2, γ-IFN and TE in group C tended to reduce but without significance, compared with group A. (2) Compared with group B, ACTH value in group C was very significantly lowered than that in group B (P〈0.01), and CRH value was lower while CORT value was higher than those in group B but without significance (both P〉0.05). The values of TE and γ-IFN in group C were significantly higher than those in group B (P〈0.01, P〈0.05). Conclusion (1) Long-term of intense exercise induces ac