The invention belongs to the technical field of rapid solidification of amorphous alloy and concretely relates to an iron-based amorphous alloy broad ribbon, wherein the width is 220-1000 mm, the thickness is 0.02-0.03 mm, the transversal thickness deviation is smaller than +/−0.002 mm, the lamination factor is larger than 0.84, the saturation magnetic-flux density is larger than 1.5 T, the iron loss is smaller than 0.20 W/kg under the conditions that the frequency is 50 Hz and the maximum magnetic-flux density is 1.3 T, and the exciting power is smaller than 0.50 VA/kg. The invention also relates to a manufacturing method of the broad ribbon, and a single-roll quenching method is adopted, wherein the width of a nozzle slot is 0.4-0.7 mm, the transversal width deviation of the nozzle slot is smaller than +/−0.05 mm, the transversal flatness deviation of a cooling roll (4) is smaller than 0.02 mm, and the surface roughness Ra is smaller than 0.0005 mm.