This work focus on evaluating the influence of B site partial substitution on the physicochemical property and the catalytic property of La0.8Ce0.2M0.25Co0.75O3 (M = Cu, Mn, Fe) perovskite catalysts in NO reduction by CO. The partial substitution of B site in La0.8Ce0.2CoO3 perovskite significantly improves the catalytic performance, following the order: La0.8Ce0.2Cu0.25Co0.75O3 > La0.8Ce0.2Fe0.25Co0.25O3 approximate to La0.8Ce0.2Mn0.25Co0.75O3 > La0.8Ce0.2CoO3. The best catalytic property is achieved over La0.8Ce0.2Cu0.25Co0.75O3 catalyst at 300 degrees C, with 99% N-2 selectivity and nearly complete conversion for NO and CO, respectively. Simultaneously, La0.8Ce0.2Cu0.25Co0.75O3 perovskite catalyst reveals the promising long-term catalytic property, compared with La0.8Ce0.2CoO3. The texture property, reducing capacity, and percentage content for oxygen defects of modified perovskites are considered as the decisive factors for the enhanced catalytic property. Moreover, giving La0.8Ce0.2Cu0.25Co0.75O3 perovskite as an example, the overall catalytic process is tentatively presented to completely understand each reaction step in NO reduction by CO.