The three main characteristics of benign tumors are mainly reflected in high degree of differentiation, non-invasive growth and no distant metastasis, contrary to the characteristics of malignant tumors. Benign tumors generally have relatively small effects on the organism, mainly manifesting as local compression and obstruction symptoms, which are related to the size and location of the tumor.1. High degree of differentiation: When there are abnormalities in the morphology, metabolism and function of tumor cells, there will be different degrees of loss of differentiation and maturation ability, and generally benign tumors are highly differentiated. Heterotypy is a manifestation of maturation disorder and differentiation disorder of tumor tissues and cells. Benign tumor cells have small heterotypy, but still have different degrees of structural heterotypy; 2. Non-invasive growth: benign tumors in parenchymal organs mostly show swelling growth, slow growth rate, clear tumor boundary, can form complete fibrous perithelium, and good mobility. With the increase of volume, it can compress the surrounding tissues and produce symptoms, which can generally be removed by surgery. Tumors on the body surface as well as in the body cavity can be exophytic and generally will not infiltrate to the base; 3. No distant metastasis: benign tumors will not have distant metastasis, spreading to distant places is the most important biological feature of malignant tumors, through this feature benign and malignant tumors can be distinguished.