Broadening the effective temperature range (window) of NO removal on Co . Pd-modified H-ZSM-5 (Co/Pd/H-ZSM-5) in the presence of methane under an excess-oxygen condition was tried under the concept that the lack of the amount of methane occurred by CH4 combustion at high temperature reduced NO conversion to N-2. The activity for NO removal of the catalyst at high temperature was improved due to suppression of methane combustion by the thermal treatment of Pd in a H-2-containing flow. Co/Pd/H-ZSM-5s with and without the thermal treatment of Pd showed different temperature windows for NO elimination. These different windows were then combined by a two-stage catalyst packing, in which Col(Pd/H-ZSM-5)(red), and Co/Pd/H-ZSM-5 were placed in series, resulting in the broadening of the window.