Hierarchical pine tree-like α-MnO₂ architectures are prepared by a facile one-step method without any template. The hierarchical α-MnO₂ is composed of branched α-MnO₂ short nanorods assembled onto the backbone of an α-MnO₂ long nanowire. Time-dependent experiment shows that the growth process of the branched α-MnO₂ nanostructures is the formation of β-MnOOH and then the transformation to a α-MnO₂ branched structure in a step by step manner. Owing to its specific structure features, the hierarchical pine tree-like α-MnO₂ exhibits superior catalytic performance in the catalytic combustion of dimethyl ether with a light-off temperature (T₁₀) at 169 °C and a complete conversion temperature (T₉₀) of 235 °C, which is far better than commercial MnO₂.