The invention discloses a manufacturing method of amorphous alloy iron cores, which comprises the following steps of: (1) cutting and overlapping an amorphous alloy belt material to obtain iron core overlapped sheets comprising multiple groups of amorphous alloy sheets; (2) suiting and molding the iron core overlapped sheets so that the two ends of the amorphous alloy sheets of each group are jointed to obtain molded iron cores; (3) carrying out magnetic heat treatment on the molded iron cores; and (4) coating the surfaces of the molded iron cores. The amorphous alloy iron cores produced by using the method can meet the requirements of the transformers with different capacities, has convenient operation and high degree of automation, is suitable for the batch production of the amorphous alloy transformer iron core, is beneficial to the popularization and application of the novel energy-saving products of the transformers, and greatly relieves the conflict of the domestic electricity overload.