Abstract: In order to get good metallographic structure of diffusion coatings,a lot of experiments were done on the sample preparation routines based on Struers sample preparation equipments for chromising and aluminizing coating by chemical vapor deposition (CVD) method. A serious of metallographic sample preparation methods with good repeatability and performance were summarized. Electroless nickel plating and low porosity dialylphtalate thermosetting resin was proved to have excellent edge retention function.