Abstract: A total of 2 800 273-day-old healthy parental brown Roman breeding layers were randomly divided into five groups. The group Ⅰ was the control group, and the groups Ⅱ,Ⅲ, Ⅳ, and Ⅴ were the experimental groups. The trial last for seven weeks, one week of which was pre-feeding period and six weeks of which was experimental period. The Yikang XP was added to the diet of the experimental groups （ Ⅱ,Ⅲ,Ⅳ, and Ⅴ） at the ratio of 0.15 %, 0.25 %, 0.3 %, and 0.5 %, respectively. And the chickens of group I were fed with the basal diet. The results showed that the addition of Yikang XP at the ratio of 0.3 % promoted the laying rate of breeding layers and reduced feed intake.