The invention discloses a three-dimensional microcolumn array active electrode based on a tubular metal oxide and a preparation method thereof, which belong to the field of micro energy storage devices. The three-dimensional microcolumn array active electrode is formed by sequentially attaching Si/SiO2, a three-dimensional microcolumn array electrode, a nano metal oxide active electrode thin filmand a current collector of the three-dimensional microcolumn array electrode onto a silicon substrate. The nano metal oxide is selected from ruthenium oxide, manganese oxide and the like. The preparation method comprises the steps of: firstly, processing microcolumns and ''micrograss'' structures; and then taking the ''micrograss'' structures as a deposition template, and preparing a three-dimensional tubular nano metal oxide thin film, so as to obtain the three-dimensional microcolumn array active electrode. The tubular microstructures promote the improvement of the specific surface area of the electrode, thus the electrode has excellent electrochemical energy storage property, the specific capacity is up to 99.3 mF/cm<2>, the tubular microstructures are applied to a supercapacitor electrode, the improvement of energy density and power density of the micro energy storage device is effectively promoted, thereby helping the application of the three-dimensional microcolumn array active electrode to wearable electronic devices and wireless sensor networks.