Abstract: Zigzag char surface model was applied to investigate the heterogeneous reduction mechanism of N2 O by char through the density functional theory in quantum chemistry method. Firstly,the fundamental differences between Zigzag and Armchair char model were analyzed,and then the thermodynamic and kinetic analysis were conducted to reveal the heterogeneous reaction mechanism of N2 O by char. Finally,the calculated results of Zigzag and Armchair models were compared and analyzed. Research results show that the heterogeneous reduction of N2 O by char includes adsorp- tion,reduction and desorption process,and the desorption process of N2 is a reaction rate determining step. The reduc- tion reaction is spontaneous and exothermic reaction,and takes place in one direction owing to that the reaction equi- librium constant is greater than 105 in the circulating fluidized bed furnace temperature range. According to the theory of reaction rate determining step,the reaction activation energies are 160. 99 kJ / mol and 66. 28 kJ / mol for Armchair and Zigzag model,as well as Arrhenius expressions are 3. 99×1015 exp( -19 364. 0 / T) and 1. 07×1014 exp( -7 972. 4 /T),respectively. Reaction activation energy is smaller and rate constant is greater in Zigzag model than Armchair,which indicates the reaction is more active under Zigzag model. Additionally,since there are lone pairs in Zigzag mod- el,the chemical properties of Zigzag model is more active,which makes a different calculated results comparing with Armchair model. Thus,the effect of different calculated models on studying reaction process should be considered in the carbon-based theoretical calculation.