Objectives The protective mechanism of selenium against cellular damage in animals at the cellular level was reviewed to provide reference for the application of selenium in animal production. Methods The multiple physiological functions of selenium were summarized. The effects of selenium on alleviating oxidative stress, enhancing immune function, and antagonizing toxic elements in livestock and poultry under cellular damage were discussed. Results Selenium has the effects of antioxidant stress, enhancing immune function, and antagonizing toxic elements. It can be used as a good alternative to antibiotics to improve the production performance, immune function, antioxidant capacity, and the intestinal health of poultry. Conclusions Selenium can be used as an effective antidote and protector in animal production.Current studies on selenium regulation of cellular damage in animals are relatively less focused on livestock,and there are few reports on the synergistic and correlated regulatory mechanisms between signaling pathways and other signaling pathways, which require further in-depth study.