We constructed the AFP promotor, suicide gene and EGFP eukaryotic expression vector recombinant plasmid, and this plasmid DNA was encapsulated by biodegradable, biocompatible polymer PLGA to prepare nanoparticles. The results demonstrate that the mean diameter of DNA-PLGA-NP is 68 nm, the encapsulation ratio reaches to 80%, and the PLGA nanoparticles can protect plasmid DNA from digestion by deoxyribonuclease I (DNaseI) and sonication-induced shearing in vitro.