ObjectiveTo summarize the research progress in the study of the diagnostic function of humoral circular RNAs in human diseases.MethodsThe research progress was summarized by reading relevant literatures on the diagnostic function of humoral circular RNAs in human disease at home and abroad.ResultsAs endogenous circular RNA molecules, circular RNAs were found to be related to a variety of diseases due to their stable structures, conserved sequences, diverse functions, and tissue cell specificity. Recent studies had found that circular RNAs could be secreted into body fluids, such as blood, saliva, urine, gastric juice, seminal plasma, and so on. They could also exist in body fluids stably. In addition, circular RNAs were found that was related to the diagnosis of various diseases, including cardiovascular diseases, nervous system diseases, autoimmune diseases, various carcinomas and metabolic diseases, and so on. As a consequence, circular RNAs might be important biomarkers for non-invasive detection of human diseases.ConclusionsRecent researches have found that circular RNA is related to the diagnosis of various diseases. Therefore, the in-depth study of the relationship between humoral circular RNAs and the diagnosis of diseases is conducive to the development of non-invasive diagnostic markers of clinical diseases, which is of great significance for the non-invasive diagnosis of diseases.