Herein, a facile solution-phase method is used to fabricate Mn3O4 nanowires. The structure, morphology and chemical composition of the crystals are characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy. It is interesting that a morphology evolution can be induced by changing the reduction temperature, during which Mn3O4 nanoparticles and Mn2O3 nanostructures can also be obtained. Furthermore, asymmetric supercapacitor cell is utilized as a device to evaluate the capacitive performance by cyclic voltammetry and galvanostatic charge-discharge test. Electrochemical results show that the prepared Mn3O4 nanowire exhibits enhanced charge storage properties, which could promote its application in energy storage devices. Graphic abstract