A series of novel naphthalimide derivatives modified by amino acids and their dichloroacetamide derivatives at the 3-position have been synthesized. Their cytotoxic activities were preliminarily evaluated against Hela, A549 and K562 cells, which showed that the length of the side chains of the amino acids influenced the cytotoxic activities. Moreover, compound 7d showed a very good cytotoxic activity against A549 cells with an IC50 value of 4.78 mmol Là1. Furthermore, the UV–vis, fluorescence,and circular dichroism(CD) spectroscopies and thermal denaturation experiment indicated that compounds 6a, 6d and 7a, 7d, as DNA intercalators, exhibited binding affinities with calf-thymus DNA(Ct-DNA).