A series of La_1−xBa_xCoO₃ (x = 0, 0.1, 0.2, 0.3) perovskites were synthesized by the modified sol–gel method, and their activities for NO oxidation were investigated as well. The relevant structural characterizations of the prepared catalysts were conducted by XRD, ICP, BET, FTIR, TEM, H₂-TPR and NO-TPD. The performance evaluation indicated that introduction of Ba at the A-site in LaCoO₃ greatly improved the activity for NO oxidation. The best performance with NO conversion of 93% at 265 °C was obtained on La_0.9Ba_0.1CoO₃. Additionally, the Ba-doped LaCoO₃ had better performance than that of the classical Pt/Al₂O₃ catalyst, implying that the non-noble catalysts could be considered as potential substituting candidates for noble metal-based catalysts.