Abstract: In order to enhance the catalytic performance at low flue gas temperature and broad its catalytic activity temperature, cobalt modified industrial V-Mo/Ti De-NO_x catalysts were prepared by impregnation method. XRF,N_2-adsorption desorption, H_2-TPR,Raman spectrum and NH_3-TPD were used to characterize the catalysts. The denitrification performance and resistance to SO_2 and H_2O of the different catalysts were tested by a fixed-bed micro-reactor. The results show that the loading of CoO has little impact on the pore structure and crystal structure of V-Mo/Ti catalyst. The structures of VO_x and MoO_x species of V-Mo-Co/Ti catalysts are similar to that of the V-Mo/Ti catalyst. Suitable amount of CoO(0.28%) can lead to the enhancement of acidity of the catalyst, without decreasing the reducibility of the catalyst. As a result, the catalyst activity is improved. When the flus gas temperature is 280 ℃,the NO_x conversion of CO-2 catalyst with 0.28% CoO is above 80%. However, excessive loading of CoO might results in the coverage of active sites by CoO,which reduces the chances of contact between VO_x species and the reaction gas. Consequently, the catalytic activity of the catalyst decreases. Besides, this study also finds that the SO_2 and H_2O resistance of the catalyst can be effectively enhanced by Co modification.