Abstract: In order to understand the characteristics of the immune adverse effects of avian infectious laryngotracheitis attenuated vaccine, the experiment summarized the change rules of adverse effects, clinical manifestations and pathological changes of the chicks from five layer brood households in Zhangjiakou City, Hebei Province after being immunized with the infectious laryngotracheitis attenuated vaccine; the reasons were analyzed, and a prevention and control plan was put forward. The results showed that chicken flocks generally had mild immune adverse effects on the second day after immunization, and the reaction worsened on the 3 rd and 4 th day after immunization, and gradually got better on the 5 th and 6 th day after immunization. The clinical symptoms were 0.03%-0.19% of respiratory diseases during night auscultation; the feed intake of chickens 1-7 days after immunization decreased by 11.6%-21.1% compared with 1 d before immunization, and the uniformity of body weight decreased. Necropsy revealed inflammatory reactions in the larynx, trachea, and bronchi; the mucous membrane surface was covered with mucus, and blood clots appeared in the trachea. The results suggested that the immune adverse effects of infectious laryngotracheitis attenuated vaccine were mainly manifested in the respiratory system and eyes. Under the premise of achieving vaccine use and rationalization of the immunization process, auxiliary ventilation management in the house before, during and after immunization could effectively reduce the incidence of immune adverse effects.