To observe the effects of acupuncture on event related potential P3(P3) in children with attention deficit hyperactivity disorder (ADHD), P3 in 40 ADHD children and 20 normal children was detected.It was founded that the occurrence rate of P3 in ADHD chilthen under the situations of active retention and passive attenhon was 68.9% and 46.6%,and 94.3% and 35.7% in normal children respefavely(P