The present invention discloses a trinickel disulfide film electrode directly grown on a foam nickel substrate and a preparation method thereof. The foam nickel is used as the substrate and a nickel source, thiourea is used as a vulcanizing agent, and glycol is used as a solvent. The trinickel disulfide film electrode directly grown on a surface of the foam nickel is obtained through a simple solvent thermal method. The preparation method has the advantages of simple process and low costs, and is applicable to large-scale industrial production. The present invention further discloses application of the trinickel disulfide electrode. The trinickel disulfide film electrode has a porous nanometer structure, so that a material and an electrolyte can contact fully. The trinickel disulfide grows on the nickel source, that is, the foam nickel, and is firmly combined with the substrate, so that the electric charge can be transferred rapidly. The prepared trinickel disulfide has high rate performance and excellent circulation stability, and is an ideal super capacitor electrode material.