To investigate the effects of dietary supplementation SQ (squalene) on the growth performance, antioxidant capacity and immunity function of broilers at age of 1-21 days, 360 one-day-old male AA⁺ boilers with body weight (38.38±0.25) g were randomly divided into 3 groups by single-factor experiment, with 6 replicates per group and 20 boilers per replicate. Broilers in CK group were fed with the basal diet, and experimental treatment groups were fed with basal diet with 175 and 350 mg·kg^-1 SQ, respectively. The experiment lasted for 21 days. The results indicated that: (1) Dietary supplementation of 175 and 350 mg·kg^-1 SQ significantly increased the average ADG (average daily gain) and significantly reduced the F/G (P < 0.05). Dietary supplementation of 175 and 350 mg·kg^-1 SQ significantly increased serum SOD, GSH-Px, CAT and T-AOC activities in broilers (P < 0.05), significantly reduced serum MDA content (P<0.05), and compared with 175 mg·kg^-1, dietary supplementation of 350 mg·kg^-1 SQ significantly increased serum CAT and T-AOC activities in broilers. (2) Dietary supplementation of 175 and 350 mg·kg^-1 SQ significantly increased the serum HDL level, complement C3 and C4 levels in broilers(P < 0.05), and significantly reduced the serum LDL level in broilers(P < 0.05). Compared with 175