The invention discloses a heat exchanger of an indirect hot-blast stove. The heat exchanger comprises dissipating pipes, dissipating boxes and connecting rods, wherein the dissipating pipes are inverted U-shaped round pipes; dissipating intervals are arranged between the dissipating pipes; ventilation intervals are arranged between the heat dissipating boxes; the top of a first dissipating box communicates with the top of a second dissipating box through a first row of the dissipating pipes; the top of a second dissipating box communicates with the top of a third dissipating box through a second row of the dissipating pipes; the bottoms of the end walls of the same ends of the first heat dissipating box, the second heat dissipating box and the third heat dissipating box are each provided with an ash removal opening; each ash removal opening is provided with an ash cover; a total smoke outlet is arranged at the top wall of one end, close to the ash removal openings, of the first heat dissipating box; a total smoke inlet is arranged at the bottom wall of the other end, opposite to the ash removal openings, of the third heat dissipating box; the lengths of the heat dissipating boxes are equal, and the widths of the heat dissipating boxes are sequentially increased from the third heat dissipating box to the first heat dissipating box; the connecting rods are respectively arranged on the top walls of the two ends of the heat dissipating boxes; and each connecting rod is simultaneously fixedly connected with the first heat dissipating box, the second heat dissipating box and thethird heat dissipating box.