Abstract: The effects of extraction time,alkaline concentration,and the addition of cartilage on the extraction of mucopolysaccharides from shark fin cartilage digested with NaOH were investigated.The main components of mucopolysaccharides during the degrading process were analyzed by cellulose polyacetate strip electrophoresis and agarose gel electrophoresis.The results showed that the extraction of mucopolysaccharides was increased with the increase of extraction time,alkaline concentration and the addition of cartilage.According to the different electrophoretic migrations,the preparative mucopolysaccharides composed of different polysaccharides with electronegativity can be divided into two parts,the chondroitin sulfate with higher migration and the other with lower migration.The lower part is unstable and easily degraded with alkaline solution.