The delta strain is a new crown variant of the virus, which has not only increased its transmission capacity, but also its virulence. Patients infected with the delta strain usually have atypical clinical symptoms, with a low probability of developing fever in the early stages. They may have symptoms of severe colds such as sore throat, runny nose, impaired sense of smell, body aches, etc., as well as conjunctivitis, rash, diarrhea, abdominal pain, bleeding from the mouth and nose, and in severe cases, they may have blurred consciousness. Patients who have these symptoms, or who have traveled to moderate or high risk areas, or who have a history of close contact with a confirmed diagnosed person, need to report and undergo a nucleic acid test to help confirm the diagnosis. Chest CT may also be performed to observe the patient’s lung lesions, which generally progress significantly in heavy patients, with more than 50% of the lesions apparently progressing within 24-48 hours. Delta strain is more contagious, must pay attention to good personal protection, it is recommended to go out and wear a mask, wash hands diligently, diligent ventilation, and avoid going to crowded places. Meanwhile, it is important to receive the new crown vaccine in time to reduce the chance of infection, reduce the rate of severe illness and mortality.