Yin and yang is the core concept of traditional Chinese medicine theory system. The discussion of yin and yang in Suwen · Yin-yang Yingxiang Dalun as 'the accumulation of yang is the heaven and the accumulation of yin is the ground' and 'the lucid ascends to form the heavens while the turbid yin descends to constitute the earth' showed that in the human body, the qi of the clearing yang rises in the upper part, and the qi of the turbid yin descendsin the lower part because of the theory of relevant adaptation of the human body to natural environment. The discussion of lucid yang ascending to the upper orifices and turbid yin being discharged from the lower orifices, lucid yang spreading into the body surface andturbid yin goes five zang viscera, lucid yang replenishing four extremities and turbid yin returns to the six fu viscera in Suwen · Yin-yang Yingxiang Dalun told us that yang master ascending and in the upper, and yin master descending and in the lower, which was the nature of yin and yang. However, in reality there was a phenomenon contrary to this theory, such as cloud formation, climate change, coordinating water and fire, mutual transformation of qi and blood, liver ascending and lung descending, spleen ascending and stomach descending, coordination between the heart and kidney, traditional Chinese medicine therapy, ascending and descending compatibility of traditional Chinese medicine, and so on. The author through that yin ascending and yang descending was an important form of the movement of yin and yang. This paper elucidated the scientificity of yin ascending and yang descending based on divination and qi theory, in order to provide scientific basis for application of theory of yin and yang in clinic and academic research.