Oral mucosal disease is a disease in which the normal color, shape, integrity and function of the mucosa of an area of the oral cavity are altered. There is a wide variety of lesions that can be combined into complex and diverse damage. Some systemic diseases are also manifested in the oral mucosa, while some oral manifestations can be used as a basis or clue for the diagnosis of systemic diseases. In terms of their pathogenesis, except for a few directly related to oral conditions, the majority are closely related to systemic or systemic factors. With the continuous development of immunological research, oral mucosal diseases related to autoimmunity have been found to be clinically common, such as aspergillosis, pemphigoid, Scheugrin’s syndrome, and nodular disease. The etiology of oral mucosal diseases is still unclear, except for some diseases whose etiology is clear. The main causes of oral mucosal disease: 1, with the age of people, oral immunity decline physiological defects related to adults due to the reduction in the secretion of growth hormone, oral absorption capacity for vitamins than children during the growth period; 2, recurrent oral ulcers belong to polygenic genetic disease, parents are more serious, the possibility of children inherited on the great. Especially the elderly, the body is prone to gastrointestinal disorders, lack of iron, zinc and other trace elements in the body, poor sleep leading to mental tension, fatigue or cold, can trigger mouth ulcers.