Economic efficiency and emission performance of lean combustion gasoline engine are significantly impacted by the contents of CO

2

and vapor. Modeling of NO

x

adsorption process is conducted considering the ash core model theory. The experimental data are set as the inlet boundary conditions

and the adsorption process with CO

2

vapor or the both is analyzed. Following the original adsorption mechanism of the added BaO and Ba(OH)

2

in the process

three kinds of catalysts

i.e.

Bao

Ba(OH)

2

and BaCO

3

are investigated with different CO

2

and vapor contents. The results show that CO

2

significantly reduces lean NO

x

trap(LNT)adsorption efficiency compared with non-CO

2

adsorption efficiency

but the adsorption efficiency nearly remains constant with increasing CO

2

concentration. The influence of vapor on adsorption efficiency is negative to a certain extent and weaker than that of CO

2

but gets stronger with the increasing vapor. If both CO

2

and vapor exist

the adsorption efficiency stands between the cases of sole CO

2

and sole vapor.