Recently, at a symposium organized by the Peterson Institute for International Economics, some scholars argued that the benefits of a floating exchange rate mechanism were exaggerated and that floating exchange rates were sometimes "can be lethal to small countries ". When a country's currency appreciates, it can encourage the inflow of hot money to create an asset bubble. Then, when investor sentiment changes, the sudden capital outflows can trigger a recession. It can be seen that the shortcomings of the floating exchange rate is obvious, hence it is not the best exchange rate mechanism. Scholars in the West have now put forward new challenges for the exchange rate mechanism.