Tremendous progresses have been made in natural disaster monitoring, forecasting and early warning since the reforming and opening of China. These developments have played an important role in reducing economic losses, guaranteeing the safety of peoples lives and property, and promoting social stability and prosperity. But it should be soberly recognized that under the new situation of natural disasters and socioeconomic development, natural disasters still pose a great threat to China's national and public safety. Compared with the international advanced level, and the needs of the “three transformations” in national disaster prevention and reduction strategy, there is still a large gap in ability of disaster monitoring and early warning. This paper briefly discusses the impacts of five kinds of natural disasters on national public security: weather, ocean, geology, earthquake and Biology. And based on the current capacity and existing problems in natural disaster monitoring and warning, the strategies of science and technology development for natural disaster monitoring and warning in the coming 5-10 years are put forward, which include: 1) strengthening theoretical researches on disaster forecasting and prediction; 2) enhancing comprehensive monitoring capability; 3) constructing disaster warning systems of more efficient; and 4) developing disaster mitigating, avoiding and relief technologies.