The invention relates to a special sealant mildewproof agent for a biological kitchen. The formula of the special sealant mildewproof agent mainly consists of microalgae active enzyme, biological active polypeptide, seaweed biological polysaccharide, amino acid salt and chitin. The special sealant mildewproof agent is added in the production process of sealant and used for preventing the mould and free from damaging the application performance of the sealant. The special sealant mildewproof agent has the following advantages: (1) the sealant mildewproof additive is durable for resisting the bacteria, wide in bacterial resisting range and capable of resisting multiple bacteria; (2) no irritating component is contained, and no toxicity on the human body and food exists; (3) the nature is mild, and the biological component does not influence the performance of the sealant; (4) the special sealant mildewproof agent is first fused with the cross-linking agent of the sealant so as to promote the cross-linking action of the sealant, and the performance of the sealant is firmer.