Modified Early Warning Score system can help medical staff to identify patients with “potential critical illness” at an early stage and effectively reduce the death rate. In 2001 the NHS recommended MEWS for general practice assessment. However, there are few studies on MEWS in general departments, and the specific application effect is still being explored. Therefore, this paper summarizes the application advantages, application methods and application effects of MEWS in general departments at home and abroad, so as to provide some theoretical basis for the development of MEWS in general departments. After summary, it was found that although MEWS evaluation indicators are simple and easy to obtain, and can facilitate the communication of medical conditions, MEWS has a poor ability to identify “potential critically ill patients” in general departments. The role of predicting the prognosis of patients in general departments remains to be explored. A large number of multi-center, large-sample and large-range studies are needed to provide a basis for the application of MEWS in general departments.