The invention relates to an ammonia neutralization device and method. The device and the method are mainly used for solving the problems in the prior art that the rate of removal of ammonia from reactant gases in an ammonia oxidation reaction is low, the ammonia enters a subsequent system, the polymer loss of organic matters is increased, the clogging to towers and pipelines is caused, and the operation cycle of equipment is shortened. According to the ammonia neutralization device and method, by adopting the technical scheme that the ammonia neutralization device comprises a shell, a reactant gas inlet, a reactant gas outlet, a reactant gas neutralizing solution inlet and a reactant gas neutralizing solution outlet, a tower plate or filler which is located below the reactant gas neutralizing solution inlet and above the reactant gas inlet is arranged in the ammonia neutralization device, a liquid distributor is arranged at the neutralizing solution inlet, and a reactant gas neutralizing solution is in counter-flow contact with the reactant gases, the problems are better solved, and thus the device and the method can be applied to an industrial unit for the ammonia oxidation reaction.