NOVELTY - A metallic oxide with a gradient structure, heterogeneous structure, where one elements form crystal seed and the other elements form different oxides.    USE - As metallic oxide with a gradient structure (claimed), used as materials for positive/negative electrodes of fuel cells.    ADVANTAGE - The metallic oxide improves the efficiency of the materials as a photochemical catalyst or reduces the polarization of electrochemical reactive process, improves the electrochemistry efficiency, and the materials are higher in photocatalysis or electro-catalysis efficiency corresponding to the traditional oxides with uniform structures.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparing metallic oxide with gradient structure, involving preparation of parent metal oxide: preparing the parent metal oxide by hydrolysis, hydrothermal, alcohol heating or microwave, and ultrasonic methods, producing a precursor oxide core by a parent precursor; introduction of gradient elements: adding the introduced element for forming heterojunction into a reaction system by dripping, injection adding or precursor way, entering an inner part in process of generating parent and replacing the relevant metal ions in the parent lattices, forming the heterogeneous structure; forming and generating the gradient structure: while the reaction is continuously carried out, gradually increasing the concentration of heterogeneous elements and reducing the concentration of the parent ions, forming the heterogeneous structure in the metallic oxide, while the materials are generated continuously, gradually reducing the concentration of the parent ions in a radial direction from the core to a shell, and forming the gradient distribution structure with gradually increased concentration of the heterogeneous elements, and finally forming the structure of the different element oxides distributed in an island way on the surface; and 4) drying and separating the oxide with gradient structure: separating the prepared oxide from the system as a catalyst, a precursor of the catalyst or a carrier.