The interspecific relationships of the genus Leucophenga, L.concilia, L.maculata, L.orientalis , and L.quinquenmaculipennis were investigated by soluble proteins analysis. the electrophoretic banding patterns of the four species analyzed by SDS-PAGE were scanned by densitormeter. The soluble protein patters of L.maculata and L.concilia by SDS-PAGE appeared similarly and on the other hand, those of L.quinquemaculipennis had a different forms from three other species. The genetic distance among the four species of TDE analysis was calculated by formula of the Aquadro and Avis(1981) . The genetic distance between L.maculata and L.concilia was 0.393 , the lowest of all and between L.maculata and L.quinquemaculipennis was 0.496, the highest of all. The dendrogram was established using UPGMA method based on genetic distance obtained by TDE analysis. Clustered patterns as follows ; first, L.maculata and L.concilia were clustered, and L.orientalis and L. quinquemaculipennis followed the firstone in order. In consequence, it seems that the interspecific relationship of L.quinquemaculipennis was farther from the other three species, while that of L.maculata and L.concilia was closer than that of L.orientalis.