[Objectives] The purpose of this experiment was to study the effects of dietary supplementation of Herba Picriae extract on the growth performance and immune organ index of Guangxi partridge chickens. [Methods] A total of 500 one-day-old Guangxi partridge chickens were selected and randomly divided into five groups, five replicates for each group and 20 chickens for each replicate. Groups A, B and C were treatment groups, in which 0.70%, 0.35% and 0.175% of Herba Picriae extract was added to the basal diet, respectively. Group D was a positive drug control group, in which 0.01% colistin sulfate premix was supplemented. Group E was a blank control group, in which the chickens were fed the basal diet. The experimental period was 105 d. During the experiment, five chickens were randomly selected from each group on days 21, 35 and 49, respectively for the measurement of immune organ index. [Results] When the chickens were fed basal diet supplemented with 0.175% of Herba Picriae extract, their daily body weight gain increased significantly from day 22 to day 35 and from day 71 to day 105 and tended to increase from day 1 to day 21, from day 36 to day 49, and from day 50 to day 70, with a range of 7.37%-8.72%. Dietary supplementation of 0.70% and 0.175% of Herba Picriae extract significantly promoted the growth and development of Fabricius bursae in the experimental chickens. [Conclusions] Dietary supplementation of 0.175% of Herba Picriae extract improved the growth performance and feed intake, as well as 21-d-old bursal index of the experimental chickens.