As an important part of the tongue image,tongue coating is a significant basis for the TCM syndrome differentiation and treatment.So the physiological and pathological mechanism of the formation and change of tongue coating is an important scientific problem.In recent years,researches indicate that in addition to apoptosis related genes,epidermal growth factor(EGF) also plays an important role on the formation process of tongue coating.This article tries to make a summary of relative study in order to provide foundation and reference for further research on the mechanism of EGF influence the formation of tongue coating.