[Objective] To investigate the effect of chitosan nanoparticles labeled with quantum dots as gene vector with pEGFP C1 plasmid on BEL-7402 cells line; [Methods] Chitosan nanoparticles acting as gene vector were prepared by polymerid dispersion method. Chitosan nanoparticles were labeled with water-soluble CdTe quantum dots which were prepared by our laboratory, and the chitosan/QDs NPs complexes were bonded with pEGFP C1 plasmid by electrostatic adsorption, in which the latter was used as reporter gene. The morphology of the DNA-chitosan/QDs NPs was observed under AFM and TEM. The cytotoxicity of chitosan/QDs NPs and proliferation of BEL-7402 cells were detected by the MTT assay. The transfection efficiency was determined by inversion fluorescence microscope and flow cytometer. [Results] Chitosan nanoparticles labeled with CdTe quantum dots could be observed high intensity fluorescence under UV transilluminator and fluorescence microscope. It was confirmed that chitosan/QDs NPs had a minimal cytotoxicity and a high efficiency to load DNA. BEL-7402 cells were successfully transfected by chitosan/QDs NPs with pEGFP C1 plasmid, and the red fluorescence from CdTe QDs and green fluorescence from enhanced green fluorescence protein (EGFP) could be both observed after 40 h incubation. [Conclusion] Chitosan nanoparticle was a novel biodegradable gene vector which has attracted a lot of attention in the field of gene transfection. In our study, chitosan NPs were successfully labeled with the water-soluble CdTe quantum dots with excellent fluorescent properties and applied in the process of gene transfection.