Abstract The magneto-impedance (MI) profiles of Co 66Fe 4NiB 14Si 15 amorphous ribbon varied sensitively with the annealing energy of the pulsed Nd:YAG laser, reflecting the change of anisotropy field which determines the field dependence of transverse permeability. Laser annealing effect of giant magneto-impedance (GMI) in amorphous Co 66Fe 4NiB 14Si 15 ribbon are discussed in terms of laser annealing energy. The pulsed Nd:YAG laser was pumped with Kr-lamp and consisted of a Nd:YAG rod of φ 5 mm×70 mm (AR coated plane/plane), a full mirror and output coupler (30% transmission). The wavelength was 1.064 μm and the pulse width was 220 μs. The GMI ratio increases with annealing energy showing largest value at 136 mJ/pulse (peak power is ∼620 W). The GMI ratio decreases with further increment of annealing energy. The decreasing H k with the annealing energy is ascribed to the increase of magnetic softness, while the increasing H k and the decreasing MI ratio for the further increment of annealing energy could be due to the microstructural change by the laser annealing.