The experiment was to explore the effect of dandelion polysaccharides on immune function, serum biochemical indexes and growth performance of broiler chickens. A total of 300 one-day-old broiler chickens were divided into five groups, with three replicates in each group with 20 chickens in each replicate. The broiler chickens in blank control group were fed with a basal diet, while the broiler chickens in positive control group were fed with basal diet supplemented with 0.2 g/kg levamisole hydrochloride, the broiler chickens in 1 g/kg dandelion polysaccharide group, 2 g/kg dandelion polysaccharide group and 4 g/kg dandelion polysaccharide group were fed with basal diet supplemented with 1, 2 and 4 g/kg dandelion polysaccharide, respectively. The trial period was 42 d. The results showed that compared with blank control group, dandelion polysaccharide groups could very extremely or significantly increase the indexes of thymus, bursae and spleen, and the contents of total protein, albumin and globulin in serum of broilers (P<0.01 or P<0.05). The content of IgG, IgM and IgA, IL-2, IL-4 and IFN-γ in serum of broilers were extremely increased (P<0.01). Serum alkaline phosphatase, urea and creatinine content of broilers were extremely decreased (P<0.01). The final weight and average daily gain of broilers in dandelion polysaccharide groups were extremely higher than those in blank control group (P<0.01), and the feed to gain ratio was extremely lower than that in blank control group (P<0.01). The experiment indicates that dandelion polysaccharide can improve the immune function, serum biochemical indexes and growth performance of broilers, the effect of 2 g/kg dandelion polysaccharide is better. [ABSTRACT FROM AUTHOR]