The invention belongs to the field of amorphous alloys, and in particular relates to an iron-based block amorphous alloy with an invar effect. A chemical formula of the iron-based block amorphous alloy is FeaMbCrcModBeCfSigPh, according to the atomic percent, b is more than 3 and less than 9, c is more than 1 and less than 3, d is more than 1 and less than 10, e is more than 5 and less than 10, f is more than 5 and less than 10, g is more than 3 and less than 8, h is more than 8 and less than 15, and the balance is a in the formula, wherein M is Co and/or Ni; and elements B and P are added in forms of industrial raw materials ferro-boron and ferro-phosphorus alloys. According to the invention, the amorphous material adopts industrial raw materials, noble metals, such as rare earth and the like, are not added, so that the cost of the block amorphous alloy is reduced; the iron-based block amorphous alloy has good amorphous formation capacity, and the critical size is not less than 2 mm; and the iron-based block amorphous alloy has the invar effect, and a Curie temperature transition point is 525-545 K.