Abstract: Nuclear fission energy has incomparable advantages in satisfying our ever growing need for energy and environmental protection. The importance of thorium-based nuclear fuel has become increasingly prominent because of its excellent breeding capability in both thermal and fast reactors, lesser long-lived minor actinides resulting from fission, and abundant reserves of thorium.One of the six IVth-generation reactor candidates, the molten salt reactor (MSR), has characteristics including high thorium energy conversion, hydrogen production at high temperature, water-free cooling, and small modular design. These properties make MSRs one of the best approaches to solve the energy and environment issues of China. 
In January 2011 the Chinese Academy of Sciences launched the“Thorium molten salt reactor nuclear energy system”project of the Strategic Priority Program, which will develop both liquid and solid fuel MSR. It will aim to realize effective thorium energy utilization and comprehensive utilization of nuclear energy in twenty to thirty years. Research has already commenced and achieved some results in key technologies. Although there are still several challenges for Th-U fuel cycle and MSR development, it can be expected that the project will help solve the energy problem as well as maintain sustainable development in China for many years to come.