Monocyte count is generally used as a reference for diagnosing diseases and has important clinical significance. Monocyte count generally refers to the proportion of monocytes in the blood and is one of the routine blood tests. It can play a reference role in the diagnosis of certain diseases and has certain clinical significance. Under normal circumstances, the reference value of the percentage of monocytes is 3%~8%, and the absolute value is (0.12~0.8)*10 to the ninth power per liter. When there is an increase in monocyte count, it may generally be caused by physiological reasons or pathologic reasons, of which physiological increase is generally in infancy and childhood, which will be slightly higher than that of adults. Pathological increases can be due to lymphoma, leukemia, Hodgkin’s disease, hepatitis, cirrhosis, and other diseases. If the monocyte count is decreased, it is usually not clinically important. The monocyte count is relatively useful, and the presence of an increased monocyte count requires specific analysis by a physician to make targeted management.