[Objective] To prepare chitosan-carbon nanoparticle and investigate its physico-chemical properties and activity in vitro. [Methods] At first, carbon nanoparticles with good dispersibility were prepared by solation method and chitosan, which delivers positive charges, was adsorbed on the surface of them to form chitosan-carbon nanoparticles using the mechanism of electrostatic adsorption. Then, plasmid DNA of PEGFP-C1 was adsorbed on the surface of chitosan-carbon nanoparticles, the former acting as reporter gene. After that, the appearances of the nanoparticles were surveyed by the scanning electron microscope; the grain distribution and zeta potentials of the nanoparticles were determined with the laser grain analyzer; the cytotoxicities of the nanoparticles to HepG2 cell and L-02 cell lines were examined by the MTT method. Later on, DNA loading efficiency of nanoparticles was examined by gel retardation assay and the gene protect action of the nanoparticles was investigated by DNaseⅠassay. Furthermore, the introduction activities in vitro of the chitosan-carbon nanoparticles were qualitatively assessed by an importation test with HepG2 cells and Cos7 cells and the results were determined by fluorescence microscope. [Results] Chitosan-carbon nanoparticles with positive charges can protect the DNA from degradation by DNaseⅠ. The polymerization index of them was less than 0.3 and the DNA loading efficiency was high certificated by gel retardation assay. The nanoparticles could enter the inner of Cos7 cells and HepG2 cells. [Conclusion] The chitosan-carbon nanoparticles can deliver the gene into cells effectively, so the chitosan-carbon nanoparticles are worth studying as gene medicine carriers.