Sharks are cartilaginous fish with fins shaped like vermicelli. From the point of view of modern nutrition, shark's fin (cartilage) does not contain any nutrients that human body is easy to lack or expensive (14 shark's fin picture), so eating shark's fin is a unique cultural phenomenon in China. Because our country is located in temperate zone, with cold winter, frequent droughts and floods, and the inland areas are far away from the ocean, the grain preservation technology is very developed, and drying and water development technology is one of the most important methods. Shrimp, sea cucumber, abalone, shark's fin, bird's nest, squid, mushrooms, magnolia slices, yellow flowers and fungus are all examples of this method. Physical and chemical changes will occur in the process of drying water. The texture and taste of food are sometimes better than fresh food, and some harmful substances can be removed. Among them, the processing and cooking technology of shark fin is very complicated and professional, and amateurs are hardly allowed to get their hands on it, which provides a reason for the high price of shark fin soup.