Abstract: In order to study the changes in the immune system of chickens in a high-concentration ammonia environment, the experiment used real-time fluorescence quantitative PCR to detect the relevant immune gene expression（MUC5 AC and E-cd genes） in the immune organs（bursa of Fabricius, thymus and spleen） of broilers treated with ammonia（15,30,60,0 mg/m~3） the situation. The results showed that at 6 weeks of age, compared with the D group, the relative expression levels of MUC5 AC and E-cd genes in the bursa of Fabricius of broilers in the B group increased by about 10 times（P＜0.05）;and the relative expression level of MUC5 AC gene in thymus increased by about 5 times（P＜0.05） the relative expression level of E-cd gene in the thymus also increased but with no significant difference compared with D group（P＞0.05）,and the relative expression level of MUC5 AC gene in the spleen also increased but with no significant difference compared with D group（P＞0.05）,and the relative expression level of E-cd gene in the spleen with significant difference compared with D group（P＜0.05）. The relative expression levels of E-cd and MUC5 AC genes was increased in bursa of Fabricius of broilers at 4 weeks of age in the B group, and the relative expression levels of E-cd and MUC5 AC genes was increased in the thymus of broilers at 6 weeks of age in the B group; The relative expression level of MUC5 AC gene in the spleen of broilers with each age was decreased in the C group. The results suggested that there were organ differences in the expression levels of MUC5 AC gene and E-cd gene of broilers were stimulated with ammonia for a long time. The bursa of Fabricius had a cavity, and the overall relative expression level of E-cd gene was elevated compared with thymvs and spleen, which was related to the structural integrity of epithelial cells.