The invention relates to the field of the manufacture of a 
semiconductor, and in particular relates to a preparation method of a TEM (transverse electric and 
magnetic field) sample. The preparation method comprises the following steps of: S1, depositing a first 
coating layer on the upper surface of a substrate; S2, 
cutting the first 
coating layer to the lower surface of the substrate; S3, preparing a second 
coating layer to cover the surface of a first cross section; S4, 
cutting the remaining first coating layer on a first sample structure to the lower surface of the remained substrate; S5, 
cutting the second coating layer to the lower surface of the remained substrate to form a TEM sample structure with a second cross section; and S6, continuously analyzing the target cross section of the TEM sample. According to the preparation method, a 
protection layer depositing method is improved, and the 
protection layer depositing time is increased, so that the thickness of the TEM sample can meet an optimal analysis thickness (40-60nm), a 
diffusion impervious layer and a 
copper interface can be clearly analyzed in the process of analysis, and the analysis quality of the TEM sample can be improved.