Malignant in clinical terms mainly means malignant tumor, which is clinically classified into the following eight points: the first point, poor differentiation. The second point, the presence of nuclear schizophrenia, mainly refers to pathological nuclear schizophrenia, commonly multinucleated, meganucleated and aberrant nuclei. The third point, growth rate, malignant tumors have a faster growth rate. The fourth point, the growth mode, malignant tumors mostly show exophytic growth and infiltrative growth. Fifth point, recurrence, malignant tumors mostly have recurrence, and the recurrence is frequent. The sixth point, secondary changes, malignant tumors mostly show bleeding, necrosis, perforation and obstruction, which are all secondary changes of malignant tumors. The seventh point, metastasis, the characteristic of malignant tumor is the existence of metastasis, which can be metastasized to lung, bone, brain and other organs. The eighth point, the impact on the organism, malignant tumor has great impact on the organism, and patients can have cachexia, which seriously endangers the health of patients.