Structure mapping theory is used in this article to analyze water by meta-theory. Through this theory, it is found a metaphorical expression that body fluid metabolism is the circulation of nature water, which means the water metabolism in TCM is metaphorically derived through analogism in accordance with the structure of circulation of nature water. From the view of water stage in nature, this could better explain function of spleen and lung in TCM. Functions of some organs are summarized through analogical reasoning by which the theory related to circulation of nature water in TCM has feature of embodied cognition.