To study the effects of dietary supplementation of Macleaya cordata extract(MCE) on the growth performance, serum biochemical indexes and intestinal morphology of Xuefeng black-bone chicks during the brooding stage, a total of 504 1-day-old Xuefeng black-bone chicks were randomly divided into 3 groups, each with 8 replicates(21 birds each replicate), and the experimental period was 42 d. During this period, the control group was fed the basal diet, and the experimental group Ⅱ(group Ⅱ) and the experimental group Ⅲ(group Ⅲ) were supplemented with 666, 1332 mg/kg MCE in the basal diet, respectively. The results showed that the body weight, daily gain, and daily feed intake of chicks in group Ⅱ and group Ⅲ were significantly(P<0.01) higher than those in control group, and those in group Ⅱ increased by 7.2%, 8.0% and 3.4%, respectively, and those in group Ⅲ increased by 9.5%, 10.3% and 5.3%, respectively. Compared with control group, the feed-to-weight ratio of group Ⅱ and group Ⅲ decreased by 4.0% and 4.4%, respectively. At 43 days of age, the serum urea nitrogen level of group Ⅱ and group Ⅲ were significantly(P<0.01) lower than that of control group, which decreased by 26.2% and 27.5%, respectively; the serum total protein level of group Ⅲ was significantly(P<0.05) higher than those of control group and group Ⅱ, which increased by 58.9% and 41.3%, respectively. The addition of MCE significantly(P<0.01) increased the villus height(VH) and the ratio of villus height to crypt depth(VH/CD) of the duodenum and significantly(P<0.05) decreased the crypt depth(CD) of the duodenum. The VH of the duodenum of group Ⅱ and group Ⅲ increased by 12.6% and 13.6%, their CD decreased by 10.5% and 14.7%, and their VH/CD increased by 25.5% and 32.9%, respectively. Compared with the control group and group Ⅱ, the VH/CD of the jejunum of group Ⅲ were significantly(P<0.05) increased by 6.2% and 2.6%, respectively. Our results suggested that the treatment of MCE in the diet could increase the intestinal morphology of Xuefeng black-bone chicks, promote the digestion and absorption of nutrients in the diet, and improve the growth performance of the chicks.