The deterioration of iron artefacts may involve a number of different decay mechanisms and produce a variety of morphologies dependent on the mode of formation of the deterioration product and the type of artefact concerned.Metal artifacts deterioration can be considered as derived from reconstructiton.It is here that discussion of the layer of band and branch microstructures observed in Koguryǒ ancient iron artefacts,which is forwardable to achieve better preserving state through metallography microscopy and SEM examination.The relative mild climate burial conditions are in favor of metal artifacts conservation,which may be one of the most important reasons that produced the solid precipitation which has a type of special morphology.