This paper makes analysis and explanation of the shortcoming and insufficiency existed in consumer demand theory under the pattern of choice cost analysis built by brand economics, revises and expands it, based on this, conducts the research on market equilibrium issue under brand choice. The research indicates that the brand realizes “brand premium” double actions and affects consumer behaviors by reducing choice cost of the consumers, improving choice efficiency of the consumers and satisfying the emotional benefit of the consumers, meanwhile, the brand affects market supply and further affects market equilibrium by implicit cost and explicit cost of brand construction, that in the market introduced the brand, the higher the brand credit is, the higher the equilibrium price is, however, the change of equilibrium quantity is determined by the consumer choice cost saved by the brand construction and by the comparative situation between the brand premium and the brand construction cost.