Introduction: Chitosan is one of the natural polymers can generally consider as a biocompatible and biodegradable polycationicpolymer, which has minimum immunogenicity and low cytotoxicity. Therefore, chitosan and its derivatives may represent potentially safe cationic carriers for use in gene delivery. Materials andMethods: Chitosan with 90.1 DD% obtained by deacetylation ofchitin extracted from local shrimp shells. Graft copolymerizationof L-lactide onto chitosan was carried out at room temperature byring opening polymerization under a nitrogen atmosphere to prepare chitosan-g-poly (N-lactide) graft copolymer. It was obtainedin good yield and characterized by FTIR. The samples purity andconcentration were detected using both Nanodrop UV-spectroscopy and agarose gel electrophoresis techniques. The humanheat shock proteins gene, hsp-70, was used as a model of humangenes to study the effect of chitosan-g-poly (N-lactide) graft copolymer. Results and Discussion: The results revealed that chitosan-g-poly (N-lactide) graft copolymers had safety effect on theDNA, and binding with it. the human heat shock proteins gene,hsp-70, was used as a model of human genes to study the effectof chitosan-g-poly (N-lactide) graft copolymer, it shows a goodbinding ability the human gene, implies that it might be used inbiomedical applications in the future. Conclusions: Grafting ofL-lactide onto chitosn by ring opening polymerization was confirmed by FTIR. The repared polymer hase safety effectson human DNA and genes. The chitosan-g-poly (N-lactide) graftcopolymer has shown highly efficiency to electrostatic interactionwith human DNA and gene, implying that it is suitable to be usedas DNA and gene delivery.