Abstract: The relationship between the serum acetylcholinesterase content, vitality and the individual development of poultry was studied from the development point. The serum, which was gotten from the different age stages of yellow feather chickens, was used as the source of acetylcholinesterase. The protein content, enzyme activity and specific activity were determined in the crude enzyme and the enzyme after dialysis. The activity of acetylcholinesterase was discrepant at different developmental stages of chicken. The protein content (after purification) , the enzyme activity and specific activity of acetylcholinesterase in 5-month-old yellow feather chicken serum were the highest. Because of getting easily, chicken blood and its serum could become cheap and abundant raw materials for the acetylcholinesterase extraction.