Nails of middle-aged and old people appear vertical lines, from the vast majority of cases with physiological factors, such as age, late night, tired, etc., but also may be associated with malnutrition and lichen planus, onychomycosis and other pathological factors. 1. Physiological factors: with age, the physiological function of the body will gradually decline, especially in the case of overwork and late night, the body will enter a state of sub-health, in this case there may be a change in the shape of the nails, in addition to other abnormalities will not be accompanied by other manifestations. 2. Pathological factors: (1) malnutrition: due to prolonged malnutrition, the supply of nutrients to the nails will be affected, so that the nails because of the lack of nutrients, and vertical lines or softening and so on. (2) Nail lichen planus: it is a chronic inflammatory skin disease, which is mainly manifested as softening, deformation and discoloration of nails when it involves nails. (3) Onychomycosis: also known as gray nails, the nails are altered due to the destruction of the nails by the ringworm bacteria. Since there are many different causes of the disease, it is necessary to consult a doctor for specific cases.