Abstract: Peroxidase isozyme was determined by polyacrylamide gel column electrophoresis method in 18 species of the Labiatae. Results showed that the band of peroxidase isozyme of those species containing diterpene quinone compounds appeared in the middle of the column with an inclination to the anode. The contents of diterpene quinone compounds in the plant were usually consistant with the band of its peroxidase isozyme. The band of peroxidase isozyme of those species containing essential oil almost did not appear in the column under the same condition.