The invention provides a supported transition metal carbide as well as a preparation method and application thereof, and belongs to the technical field of catalysts. The preparation method of the supported transition metal carbide comprises the following steps: dissolving a carbon source and transition metal salt in a solvent, carrying out solvothermal reaction to obtain a metal organic frameworkprecursor, and carbonizing to obtain the supported transition metal carbide. When the supported transition metal carbide is used as a catalyst to catalyze an ozone oxidation reaction of organic matters in water, a free radical reaction is initiated, so that the removal rate of the organic matters in the sewage is high, the removal rate is high, the mineralization degree is high, and organic pollutants with complex types in the water can be subjected to non-selective catalytic oxidation; meanwhile, when the catalyst is used, the ozone oxidation reaction can be carried out at room temperature, the consumed time is short, and the energy consumption is low; and in addition, the supported transition metal carbide is simple in preparation process and easy to form. The supported transition metalcarbide can be used as the catalyst to alleviate the environmental and energy problems, and has very strong practicability and good market prospects.