Abstract: One hundred and twenty one-day-old male or female Arbor Acres broilers were randomly divided into two groups.Each group consisted of six replicates (10 birds per replicate).Group Ⅰwas the male control and Group Ⅲ was female control fed on the basal diet,Group II (male treatment) and Group Ⅳ (female treatment) fed on the basal diet supplemented with 600 mg·kg-1 aloe powder.The results showed that the feed conversion ratio of the male treatment group was significantly higher than that of the male control group (P0.01).The ADG of both the male and female treatment groups had an upward trend compared with the control (P0.05).Index of spleen of the male treatment group was significantly higher than that of the control on 21d (P0.05).Indexes of thymus and bursa of the male and female treatment groups showed an increasing tendency compared with those of the controls (P0.05) on 21d and 42d,respectively.The level of antibody against New Castle disease virus of the male treatment group was significantly higher than that of the control on 21d (P0.05).The natural killer cell activity of the male treatment group was significantly higher than that of the control on 49d (P0.01).Consequently,aloe powder appeared to be capable of improving the productivity and immunity of the broilers.And,the greater effect was found in male than in female broilers.