Nature of Chinese materia medica is the nucleus in the theory of Chinese material medica, according to the recognition of Traditional Chinese Medicine, which is the character of the drug related on curative effect. Nature and efficacy of a drug is through the medical material, then, physical environment, including the temperature, humidity, atmospheric water, wind, topography, soil, micro-organism, and so on, influence the growth and development of the medical meterial. In this paper, we researched the explanation on nature of Chinese materia medica in the medical books of past dynasties, combined with the modem research, analyzed the relationship between generative reception and physical environmental factors, and discussed the effect of physical environmental factors on nature of Chinese materia medica. We indicated that the formation of Chinese materia medical nature is that the drug receptive the change of physical environmental factors, and resulted by the synthetic action of the factors, such as climate, soil, biology, topography, etc.