A series of novel dehydroabietylamine derivatives containing tricyclic diterpene structures were synthesized. The antitumor activities of these compounds against L02, Hey-1B and HepG2 cells were investigated. Significant activity was discovered forfourteen analogs. Meanwhile these compounds exhibit DNA cleavage activities on plasmid DNA (Escherichia coli), which depend on the Schiff base structure and the substituent of the aromatic moiety. Our findings present further information on the relationship between the chemical structure, biological function and DNA cleavage characteristics.