The problems on the duality and coherence of natural hazards, formation of anthroposphere, and preservation of ecological environment are discussed from a viewpoint of environmental system of human living as an entirety in the paper. It is suggested that the natural hazards in short time scale and small extent can be considered as a catastrophe, but in long time scale and large extent they may be a self-regulation and self balance process. There exists a bidirectional effect relation between natural hazards and human society. The coherence of natural hazards (swarm and association of their occurrence)depends on their homology, chain occurrence, and rhythm. The anthroposphere is a product of the new evolutional stage of the Earth. It is characterized by deep level,high intensity, wide activity extent, and regulation performed with information feedback. The formation of the ideas mentioned above will be of great importance in hazard study, in decrease of hazardous losses, and in breaking a new sustainable development path.