The study of foam can be traced back to Plato's time, but for hundreds of years, people have not formed a unified understanding of the definition of foam. U.S. colloid chemist L.I. osipow and r.f. Smith of Dow Corning company define the foam from the aspect of foam density; Japan's ITO Guangyi defines the foam from the perspective of foam structure, but ignores the interrelationship between bubbles; Professor Zhao Guoxi, a famous surface physicist in China, defines the foam as the dispersion of gas in liquid In the system, the gas is the dispersed phase (discontinuous phase), and the liquid is the dispersed medium (continuous phase). The bubbles in the liquid rise to the liquid surface, forming a small amount of liquid bubble aggregation separated by the liquid film. Scholars at home and abroad agree that foam itself is a kind of thermodynamic instability system, when the gas enters the solution containing surfactant, it will form a long-term stable foam system.