The types, features and causes of natural disasters are discussed in this paper.Natural disasters are divided into meteorological disaster, land disaster, oceanic disaster, biological disaster, astronomical disaster and man-made natural disaster.It is considered that natural disasters, the formations of which not only depend on natural changes but also on human activities and social-economic environment, are the synthetical reflections of nature-economy-society.Natural disasters have the characters of regionlism, periodicity, masses, chains and sociality on the basis of the laws of their formations.The main natural disasters and their damages in China are also analysed, laying emphasis on drought, flood, typhoon, earthquake, mountain disaster, dust and desertification, cold disaster, intensive convection storm, forest fire and plague of insects and mice.Finally, some basic problems of natural disaster research are discussed, including the basic theories of calamities, natural disaster monitoring technique and assessment, disaster information and management, disaster-economics and disaster-sociology.