This paper analyzes the reform of international financial system after the burst of sub-prime crisis in the following two aspects：global reserve currency and international financial institutions. There is no real constraint for the issuance of reserve currency under Dollar Standard，and it is difficult for U.S. government to balance the global needs for liquidity and domestic monetary policy stance. The resulting global imbalance and excess liquidity sowed the seeds of sub-prime crisis. The international financial institutions such as IMF have already been marginalized before the burst of sub-prime crisis. After the crisis，for reserve currency，some proposals such as creating super-sovereign reserve currency and multi-polar reserve currency have been brought forward. The crisis also speeds up the reform of IMF，especially in the areas such as expanding IMF's usable resource and increasing the flexibility of IMF's loans.