On April 5, 2009, U.S. President Obama put forward a proposal to build a world without nuclear weapons at Prague, the capital city of the Czech Republic. This is a fundamental adjustment to the nuclear strategy under the Bush administration. The proposal originates from the consideration of Americas own security interest. Objectively, it may be conducive to the safeguarding of the nonproliferation regime as well as world security and stability. However, it also has serious limitations, which will become the main obstacle to the realization of the goal of a world without nuclear weapons.