Finemet-type Fe73Si15Nb3B8Cu1 ribbon cores were prepared through adding pre-annealed treatment before crystallization annealing at 540 oC. It is found that, with an increase of pre-annealing temperature, the toughness of the pre-annealed and final crystallization annealed ribbons gradually decreased; and the second crystallization peak temperature shifted toward the higher temperature, although the difference among the first crystallization temperatures of the amorphous ribbons by pre-annealing treatment at different temperatures was not obvious. Namely, the pre-annealing expanded the crystallization annealing temperature range for the amorphous ribbon, which was beneficial to obtaining more stable and high performance amorphous nanocrystalline ribbons. The grain size of the additional pre-annealed ribbons was more uniform than that of the direct crystallization annealing ribbons, which was in the range of 8~15 nm for the ribbons by additional pre-annealing at 450 °C. The amplitude permeability and iron loss of iron cores with pre-annealing treatment had significantly improved compared with direct annealing samples, particularly, the cores pre-annealed at 450 oC had the largest amplitude magnetic permeability (μa=8.6×104, f=10 kHz) and the smallest AC core loss (P0.5/10k=8.7 W/kg), which were increased 16.0% and decreased 17.1% compared with directly annealing cores, respectively.