The invention discloses a dual-channel waste heat boiler with a function of preventing SCR (selective catalytic reduction) denitration ammonium salt crystallization. The dual-channel waste heat boilercomprises a boiler steel structure, a boiler inlet channel, a denitration outlet channel, a boiler outlet channel, a flue gas outlet, a waste heat boiler high-temperature section, a waste heat boilerdenitration section and two waste heat boiler low-temperature sections. The denitration outlet channel comprises a channel A, a channel B, a first stop valve and a second stop valve, the first stop valve is arranged on the channel A, and the second stop valve is arranged on the channel B; the boiler outlet channel comprises a channel C, a channel D, a third stop valve and a fourth stop valve, thethird stop valve is arranged on the channel C, and the fourth stop valve is arranged on the channel D; the two waste heat boiler low-temperature sections are arranged between an outlet of the channelA and an inlet of the channel C and between an outlet of the channel B and an inlet of the channel D in a one-to-one correspondence manner. The dual-channel waste heat boiler has the advantages thatthe problems of deterioration of the efficiency of existing waste heat boilers and stalling of the existing waste heat boilers due to ammonium salt crystallization can be effectively solved by the aidof the dual-channel waste heat boiler, and devices can assuredly run in long periods.