An experiment was conducted to study the extraction process of Helianthus annuus polysaccharide (HAP) and the effects of sunflower stem core and HAP powder on chicken serum interleukin-2 (IL-2). Soxhlet’s extraction was adopted to extract HAP. One hundred one-day-old Arbor Acres broilers were randomly assigned to 4 groups, with 5 replicates per group and 5 broilers per replicate. Chickens in groups Ⅱ, Ⅲ and Ⅳ were fed with basal diet, while chickens in group Ⅰ were fed with the basal diet supplemented with 600 mg/kg sunflower stem core powder. Each bird in group Ⅲ was treated with subcutaneous injection of 2 mg HAP for 7 days, while each bird in group Ⅳ was injected with 2 mg normal saline as control. Measurements of IL-2 levels in serum were taken on 12 randomly selected birds of 21 days old in each group by Chicken IL-2 ELISA Kit. The results showed as follows: 1) the content of HAP was 5.341 6%; 2) the basal diet containing 600 mg/kg of sunflower stem core powder significantly increased the content of IL-2 in serum (P<0.05); 3) the content of serum IL-2 was increased 7 days post-injection of 2 mg HAP (P>0.05). These results indicate that the basal diet supplemented with sunflower stem core powder can induce the production of IL-2.［Chinese Journal of Animal Nutrition, 2010，22（5）:1440-1444］