Cancer is one of the malignant diseases threatening human. In recent years, nanotechnology is becoming the hope the cancer treatment, as it can take the drugs targeting to tumor sites, with enhanced efficacy and reduced toxicity. Chitosan is the only alkaline polysaccharide in nature with good biocompatibility and biodegradability. Moreover, chitosan has many reaction sites to make derivatives with different properties. Chitosan and its derivatives are widely used for drug delivery systems and tissue engineering scaffolds. Hence, they are valuable in the field of biomedicine. In this paper, the recent advances chitosan nanoparticles as drug delivery system for delivering anticancer drugs are reviewed, especially the advances of the preparation, passive targeting, active targeting, and stimuli-responsive drug delivery systems of chitosan nanoparticles.