A visible nanoparticle was constructed via recombination of stearic acid modified polyethyleneimine (stearic-PEI) and superparamagnetic iron oxide (SPIO) to combine with DNA. Then through tail vein injection, the stearic-PEI/SPIO/DNA nanoparticles were efficiently delivered to BABL/c female mice that were visualized by MRI (Magnetic Resonance Imaging) and confirmed by histology. The MRI results showed that the experimental group’s T2 signal intensities significantly decrease at 0.5 h after injection, just 35% of that in the control group. Although the experimental group’s T2 signal intensities slightly recovered at 48 h after injection, there were still obvious differences between the control group and experimental group. The histological staining showed that the visible gene deliver nanocomplexes could pass through vascular endothelial cell into liver tissues and release DNA into cells, but with low gene expression effect. From the foregoing results, the nanoparticles have excellent magnetic resonance imaging performance, but low gene transfection efficiency via tail vein injection.