To investigate a possibility of the species genetic relationship for the soluble proteins analysis on the class Cephalopoda in the Yellow Sea, the isolate eye, muscle and liver proteins from five species (Sepia esculenta, Sepiella japonica, Loligo chinensis, Loligo beka and Octopus minor) were analysed using different electrophoretic techniques (Davis-polyacrylamide gel electrophoresis, SDS-PAGE, exponential gradient SDS-PAGE, thin-layer isoelectro-focusing and two-dimensional PAGE). The average molecular weight of the soluble eye and muscle proteins was estimated at 35-50 KDa, separated b the exponential gradient SDS-PAGE. It was corresponds to that of electrophoretic patterns by t재 dimensional PAGE. By which the thin layer IEF, the target proteins showed a reasonable specificity based on their isoelectric points (pI) 7.5-8.5.