A complete set of manual sample preparation methods and four compaction methods are proposed, based on the study of the mixing, humidifying, maintenance and compaction of buffer/backfilling materials. Sand was added into bentonite by step by step mixing method firstly. Then the spray on process was employed to achieve the targeted water content. The four compaction methods included dynamic compaction method with constant compaction energy, dynamic compaction method with changing compaction energy, static compaction method with constant compaction energy and static compaction method with changing compaction energy. It is found that the dry density of middle part of the sample is slightly higher than that of entire sample. Different types of samples are proposed to research the geotechnical properties of the mixed material by three variable orthogonal experimental design. It is concluded that the static compaction method with changing compaction energy can meet the requirement for both engineering and experimental research purposes.