The invention relates to a preparation method of a low-noise dry iron-core reactor with an integral compact structure. The defects of the prior art that gaps exist in the reactor to cause vibrations and movements and noises are easy to generate are solved. The preparation method comprises the following steps: 1) preparing an iron core cake; 2) preparing an iron core column; 3) sleeving an epoxy tube outside the iron core column, pouring epoxy resin adhesive in the epoxy tube, curing; 4) sleeving the coil winding poured by epoxy resin outside the epoxy tube, connecting the both ends of the coil winding with an upper cushion block and a lower cushion block; and 5) arranging yokes, wherein the upper and lower yokes are used to fix the iron core column, the epoxy tube and the coil winding. When the iron core column is prepared and the coil winding is sleeved, the pouring of epoxy resin is performed so that the entire reactor can form a compact structure and the gaps existing in the reactor can be eliminated. Therefore, noises can not be generated through the vibrations of the reactor in operation; and the displacement can be reduced.