The invention provides a method for preparing a niobium pentoxide thin film through pulse direct current sputtering. The method comprises the following steps: providing a baseplate, firstly pretreating the baseplate and then putting the baseplate in a sputtering chamber; providing a target and putting the target in the sputtering chamber; preparing the niobium pentoxide thin film on the baseplate by adopting pulse direct current sputtering under the action of a power source. According to the preparation method of the niobium pentoxide thin film, a dielectric material niobium oxide can be used as the target to prepare the niobium pentoxide thin film on the baseplate by adopting pulse direct current sputtering, thus greatly increasing the thin film growth rate, saving time and reducing the thin film preparation cost; meanwhile, the prepared niobium pentoxide thin film has smooth surface, is uniform in particle size and tight in particle arrangement and has good smoothness and compactness.