Control and preventing inflation is a focus goal in the world. Now, the price problem is widely concerned. However, the solution of the problem are more on practice monitoring and control, rather than on theoretical study The core of solutions is on policy making, price reform, price system, and price forming.So far, no paper on diffusion of price changing has been found. Actually, diffusion phenomenon exist universally in nature and social life. However, no paper linking up these problem has been found. In this brochure, we try to linking up different diffusion problems essentially by heat diffusion equation, such as: "Brownian motion" studied by Einstein; diffusion of price changing of commodity; of share prices, etc. The second linking up problems(such as: symmetric bending of shell; pred-predator system; and analysis of share-prices of A & H stock markets) with cycling differential equations have been studied by fixed point theroem of g-contraction mapping. We hope the brochure would be helpfull to readers in different areas, such as math, mechanics,finance, securities, etc.