Blood, body fluids, and tissue samples from the human body are rich in information. Any disease or condition of the human body can be determined by detecting relevant markers; this method is called "in vitro diagnosis". Immune diagnosis is a crucial part of in vitro diagnosis. Chemiluminescence immunoassay is one of the mainstream technologies for conducting immune diagnosis. Based on the principle of the specific binding of the antigen antibody, chemiluminescence immunoassay has good specificity and sensitivity in clinical applications as well as in food and environment domains. Herein, several in vitro diagnosis techniques are briefly introduced, with emphasis on the principle, classification, application field, and development trend of chemiluminescence immunoassay.