Hydrogen can selectively remove cytotoxic reactive oxygen species. The presence of hydrogen in cancer cells can affect the balance of reactive oxygen species in cancer cells, leading to apoptosis of cancer cells. In addition, hydrogen has innate advantages over drugs since it is harmless to the human body and can highly penetrate cell membranes. However, due to the diffusion of hydrogen in the body without purpose, it is difficult to achieve good curative effect by oral hydrogen-rich water and injection hydrogen-rich saline. In this paper, the mechanism of hydrogen therapy is briefly introduced, where two kinds of main nanosystems for hydrogen delivery in hydrogen therapy are introduced by enumerating some current methods of nanomaterials-based hydrogen therapy. In the end, the future of nanomaterials in cancer hydrogen therapy is prospected.