Mucosal disease is one of the most common oral cavity diseases in children, among which mucosal erosion and ulceration account for about 50%. Oral mucosal erosion and ulcer diseases in children are mostly acute with obvious pain, affecting speech, eating and swallowing. Some oral mucosal diseases are caused by infection and would result in epidemic among children. The onset age, sites, lesions size and quantity could vary, and some would have recurrence. The detailed medical history and comprehensive physical examination are necessary, some diseases can be diagnosed according to the medical history and clinical manifestations. If diagnosis can not be made, biopsy, blood test and immunofluorescence staining, immunohistochemistry, molecular biology detection, gene diagnosis, tuberculin test and other tests should be considered, and further investigation of systemic diseases should also be carried out if necessary. In some cases, multidisciplinary consultation should be sought. For those who still have no abnormal findings, therapeutic diagnosis can be tried out or secondary biopsy should be performed. In this article, the research progress of oral mucosal diseases in children is reviewed and our own clinical experiences of oral erosive and ulcerative diseases in children are summarized.