The invention provides a smoke denitrification method, comprising the following steps: after a metal cation aqueous solution serving as a complexing absorbent is atomized, spraying smoke containing nitric oxide to generate a nitric oxide complex; and decomposing the generated nitric oxide complex into nitrogen and metal cations under the acidic condition. The invention also provides smoke denitrification equipment using the method. In the method, the metal cation aqueous solution serves as the complexing absorbent, and denitrification can be carried out in a simple and easy mode so as to simplify the technical flows and eliminate the possibility of secondary pollution; meanwhile, the concentration of the metal cations is limited within the optimized range obtained from multiple times of experiments so as to improve the efficacy of the production technology; and in addition, an experiment proves that the pH value of the complexing absorbent is set to be within 6-7 so as to quicken the reaction progress and cause no adverse influence on production equipment.