The invention discloses a wastewater treatment catalyst, a preparation method thereof, and a wastewater treatment method adopting the wastewater treatment catalyst. The wastewater treatment catalyst comprises a carrier and an active layer deposited on the carrier, wherein the grain diameter of the carrier is 0.5 to 0.85 mm; an active metal layer is selected from at least one of the following materials of palladium, cobalt, nickel, manganese, tungsten and copper; the active metal layer accounts for 0.5 to 3 mass percent of the wastewater treatment catalyst. The wastewater treatment catalyst disclosed by the invention can be in efficient catalytic reaction and can be used for chemical nickel-plating wastewater treatment, test determination shows that complex nickel ions can be destabilized to form free nickel, spontaneous decomposition of a wastewater complex can be quickened, the free nickel can react with reductants of hypophosphite and the like remained in the chemical nickel-plating wastewater, an intense isotropic autocatalysis reaction appears in the chemical nickel-plating wastewater, and complicated insoluble chelation precipitate is formed by the chemical nickel-plating wastewater with a catalyst, phosphorus, alkali and the like.