The invention discloses a method for retarding natural oxidization in the mining process of ocean polymetallic sulfide, belongs to the technical field of nonferrous metal mining and relates to exploitation and utilization of metallic minerals at the ocean bottom. Polymertallic sulfide massive minerals mined from the ocean bottom are subjected to dewatering through gravity and placed in a sealed system so that air motion can be avoided, vacuumizing is conducted till the system pressure is 100-1000 Pa, and the storage time does not exceed 180 days. By the adoption of the method, natural oxidization in the mining process of the ocean polymetallic sulfide is reduced, the negative effects that part of metal ions are dissolved in water due to natural oxidization of the ocean polymetallic sulfide, and accordingly valuable metal losses and environment pollution are caused are avoided, and a foundation is laid for exploitation, smelting and utilization of the ocean polymetallic sulfide.