Abstract: Cu nanopowders were used to improve the performance of iron based alloy products formed by high velocity compaction. Under the condition that Cu powders were remain unchanged as a constant of 1.5%, part or all of Cu micropowders were replaced by Cu nanopowders. Seven kinds of iron-based alloy product samples in which the mass fractions of Cu nanopowders were 0-0.25%, 0.50%-0.75%, 1.00%, 1.25% and 1.50% respectively were prepared by high velocity compaction. The green compacts were sintered at 1150℃ for 2 h subsequently. It is found that the microstructure and performance of the iron base P/M parts is improved and the dimensional accuracy is also effectively controlled with the addition of Cu nanopowders. The tensile strength and hardness of the sintered alloy which contains 0.75% of Cu nanopowders are 720.6 MPa and 94.7 HRB, respectively. The axial and radial shrinkages of the obtained samples are in the ranges of 0.4% to 0.7% and -0.09% to -0.23% respectively when the mass fraction of Cu nanopowders is from 0.25% to 1.50%.