The paper builds a general equilibrium model to study excess liquidity and the global imbalances． The impacts of factors such as excess liquidity，savings，consumption，financial development and economic growth on the world economy are analyzed and ten important propositions are proposed． The model can theoretically explain phenomena in the world economy comprehensively，scientifically，and reasonably． The conclusions obtained can not only cover the main viewpoints of the relevant literature but also reveal the development logic of today's world economy by infiltrating the theories into the four links of social reproduction． The United States freely acquires the fruits of the development of world economy by makinguse of his international reserve currency． The United States makes a profit from fictitious economy by exchanging with the real economies of other countries according to his comparative advantage． This supports the excessive consumption in the United States and leads to the US current account deficit which contributes to global imbalances． The United States has the main responsibility for the financial crisis．