Abstract: The preparation technologies of high density iron based powder metallurgy products used in NBTM were introduced in this paper, including warm compaction, warm die compaction, double-pressing and double-sintering, and the advantages and disadvantages of these technologies were discussed. Although the preparation technologies described in this paper can improve the density and strength of powder metallurgy parts to a high level, the precision and roughness of the parts cannot meet the requirements of high-level applications, and the further machining is still needed. For the iron-based powder metallurgy parts, the precision of powder metallurgy die manufacturing, the powder characteristics, and the process stability are still needed to improve in the future, and the new sintered iron based parts preparation technology with low-cost, high-precision, and high-strength should be developed.