Abstract
Nomenclature and classification of diseases are not only related to clinical diagnosis and treatment, but also involved in the fields such as management and exchange of medical information, medical expense payments, and medical insurance payment. In order to standardize clinical physicians' diagnostic and treatment activities, medical records, and the first page of medical records, this article elaborates on the basic principles and methods for nomenclature and classification of diseases with reference to international nomenclature of diseases and international classification of diseases. Meanwhile, in view of the problems in clinical practice, this article proposes the classification of neonatal diseases, the basic procedure and writing rules in the diagnosis of neonatal diseases, and death diagnosis principles.