Western economics divides equilibrium into stable equilibrium and unstable equilibrium according to the stability of equilibrium state. As far as the equilibrium price model is concerned, when an equilibrium price system deviates from the equilibrium point under the interference of external forces, if the system can return to the original equilibrium point under the action of market mechanism, it is said that the equilibrium price system is stable equilibrium. On the contrary, if the system does not return to the original equilibrium point under the action of market mechanism, it is called unstable equilibrium. The analysis of cobweb model involves stable equilibrium and unstable equilibrium.
Cobweb theory is an economic theory about dynamic equilibrium analysis that appeared in 1930s. Its content is to investigate the influence of price fluctuation on the output in the next cycle, and the resulting equilibrium fluctuation, that is, the periodic fluctuation of price and production and sales.