In recent years, the change of biological effects in tumor cells triggered by nanoparticles had become a new breakthrough in cancer therapy. Especially, it was widely accepted that various drug loaded nanoparticles induced tumor cell death by encapsulating more drugs and depending on EPR effects to enhance the concentration of drugs in tumor sites. Nanoparticles as a useful new approach had attracted increasing attention to treat cancer. In fact, nanoparticles also played an important role on tumor cell invasion and metastasis. We used chitosan nanoparticles as a module to explore the internalization of chitosan nanoparticles on the effects of invasion and metastasis in tumor cells. Our new finding demonstrated that chitosan nanoparticles were shown to have the ability of inducing reactive oxygen species and believed to significantly enhance cell invasion and metastasis.