Fundamental properties of a shock compaction technique of applying converged underwater shock waves have been investigated for rare earth magnet powders. The rare earth magnet made from Fe-Nd-B powder is being developed to have a high magnet performance. Usually this powder is consolidated using static high pressure and bond materials. It is very difficult to obtain over 80% magnet purity and, thus, it is difficult to achieve maximum performance. To solve this problem, shock compaction techniques involving use of explosives were tested and the results are presented here. The equation of state (EOS) of Fe-Nd-B powders is first verified by a quasi -static experiment. The applicability of the EOS is confirmed by a new shock loading test which is proposed in this paper. Both numerical simulation and experiments on the consolidation of the magnet poweders are carried out. A fine-bonded bulk with of over 96% is obtained.