Foam is the result of insoluble gas entering the liquid under the action of mechanical force and being separated into non-uniform system by the liquid, thus forming a large number of gas-liquid interface. Because the density of the gas phase is less than the density of the liquid phase is less than the density of the solid phase, there will be the phenomenon of the gas phase moving to the liquid level under the action of buoyancy, resulting in two-phase foam or three-phase foam. Foaming fluid is almost always a solution, the pure liquid generally not foaming. If the liquid is stirred, a relatively stable liquid film must be formed on the surface of the liquid. At this time, the gas cannot escape outward all the time, and the bubble aggregation generated will become foam. Such isolated bubble aggregation is commonly known as foam. Foam stability on the viscosity of the liquid phase, surface elasticity, surface rheology will have a great deal of factors, generally difficult to obtain a stable and durable foam.