Abstract: After quickly remelting Fe73.5Cu1Nb3Si13.5B9 amorphous ribbons by laser,nanocrystalline bulk is gained when tiny melted pools solidified rapidly.The size of nanocrystalline bulk depends on the laser-remelting.When the input laser facula diameter is 20mm~40mm,the output facula diameter is about 2mm and!the scanning speed is 5mm/s,the nanocrystalline bulk can reach up to 2mm and the length and width are not limited.Analysis of its configuration indicates that the main phase in nanocrystalline bulk is α-Fe,the crystal constant of α-FeSi is about 25nm.At the same time,a lot of spherical Nb-rich areas appear.