The reduction ability of NO to N₂ and the oxidation performance of 1,2-dichloroethane (DCE) over α-MnO₂ catalysts were investigated. The results show that α-MnO₂-3 exhibited the highest catalytic activity in 63.5 % conversion of NO_x reduction by C₃H₈ at 250 °C, and 80 % conversion of DCE combustion by O₂ at 338 °C. It is revealed the active phase of α-MnO₂-3 is tetragonal α-MnO₂ with the selectively exposed plane of (2 1 1). It was proposed the high DCE decomposition of α-MnO₂-3 was ascribed to the redox properties. The overall characterization results revealed that α-MnO₂-3 catalyst preserves more active sites of low valence Mn and higher surface adsorbed oxygen (O_ads) /lattice oxygen (O_latt) at the outermost layers, and lower reduction temperature in H₂-TPR profiles than that of other catalysts. Meanwhile, NH₃-TPD profile of α-MnO₂-3 also shows a large number of acid sites promote NO_x reduction.