The invention provides a method for preparing a macroreticular polyvinyl alcohol foam carrier, which comprises the steps: polyvinyl alcohol, limestone and water are mixed and stirred to lead the polyvinyl alcohol to be fully and evenly dissolved; the mixture is added with dilute hydrochloric acid for acidification and is frothed to have foramen; by adopting the circulation of freezing-unfreezing, and refreezing-unfreezing again, macroreticular polyvinyl alcohol gel foam is formed; then, the polyvinyl alcohol gel foam is cut into pieces and is dipped into the dilute hydrochloric acid with the mass concentration of 0.5-1% until no bubble is generated; the polyvinyl alcohol is caused to form more stable cross-linked structure by chemical crosslinking reaction; after that, the polyvinyl alcohol is soaked in water to be washed to be neutrality, so that the white macroreticular polyvinyl alcohol foam carrier is obtained. The macroreticular polyvinyl alcohol foam carrier prepared by the invention has stable macroreticular structure, takes on good hydrophilicity, physical and chemical durability as well as biological degradability resistance, is applicable to immobilized enzyme and microorganism to form a bioreactor with multiple bed types, and can be used in the fields of modern biological engineering such as sewage disposal, etc.