In　this　current　study,　nanocrystalline　Dy　powders　were　prepared　by　melt-spinning　and　subsequent　high-energy　ball-milling.　The　effect　of　ball-milling　time　on　the　structure　and　magnetic　properties　of　the　powders　was　studied.　The　crystal　structure　and　microstructure　of　the　melt-spun　ribbons　and　ball-milled　powders　were　observed　by　X-ray　diffraction　(XRD),　scanning　electron　microscopy　(SEM)　and　transmission　electron　microscopy　(TEM).　Magnetic　measurement　of　all　samples　was　performed　with　vibrating　sample　magnetometer　(VSM).　XRD　results　indicate　that　the　average　crystal　grain　size　of　the　powders　decreases　from　90.09　nm　of　the　ribbons　to　10.42　nm　of　the　4-h　ball-milled　powders.　Further　TEM　observation　shows　that　the　grains　are　fine　and　uniform.　The　Neel　temperature　(T-N)　decreases　from　182　K　of　the　ribbons　to　172　K　of　the　powders,　while　the　Curie　temperature　(T-C)　increases　from　100　to　130　K,　demonstrating　that　the　grain　size　has　substantial　influence　on　the　magnetic　transition　process.　Moreover,　at　60　K,　as　the　ball-milling　time　increases,　the　coercivity　of　the　powders　increases　first,　peaking　at　0.48　T　for　2-h　milling,　then　drops　again,　while　the　remanence　of　the　powders　decreases　monotonically.　As　a　result,　the　powders　milled　for　2　h　exhibit　an　optimal　maximum　energy　product　of　64.0　kJ　center　dot　m(-3),　demonstrating　the　good　potential　of　these　powders　as　a　permanent　magnet　at　low　temperatures.