The invention discloses a transition metal catalyst for catalytic wet oxidation of fracturing backflow liquid and a preparation method of the transition metal catalyst. The catalyst comprises, by percent content of transition metal (namely percentage of the transition metal accounting for mass of a carrier), 1-10% of active component Cu and 1-5% of one of Cr, Ce, Ni, Mn and Zn as an auxiliary component. According to a co-impregnation method, transition metal nitrate, sulfate, acetate and chloride are loaded to the activated carbon carrier subjected to water cleaning and acid cleaning and then dried and calcined to obtain the catalyst. The catalyst has advantages of uniform dispersion of transition metal elements, favorable pore structure, freeness of precious metal components, low cost, high catalytic efficiency, high adaptability and suitableness for popularization and application to treatment of wastewater of oil and gas fields and industrial wastewater.