Foreign Ministry spokesman Qin Gang said Hu would stop in Washington for the April 12-13 summit on his way to Brazil, Venezuela and Chile.
It had not been clear if Hu would attend the U.S.-hosted event because of Chinese unhappiness over and a meeting between President , the Dalai Lama.
"The nuclear security summit will mainly discuss the threat posed by nuclear terrorism and the corresponding measures of countries and the international community," Qin said.
He called it an important multilateral meeting and said China hoped it would "yield positive results."
China reacted furiously to the U.S. decision earlier this year to sell $6.4 billion in military hardware to Taiwan, and suspended military exchanges.
The sale of helicopters, missiles and other weapons came after Obama had a White House meeting with the Dalai Lama, whom Beijing accuses of trying to separate Tibet from China.
The countries have also tangled this year over trade disputes, . and a high-profile disagreement over the value of the Chinese currency, which Washington says is being kept undervalued to unfairly support Chinese exports.
Hard-liners in the Chinese military have argued for punishing the U.S. by withholding co-operation on issues such as Iran and climate change.
Iran's top nuclear negotiator arrived Thursday for talks with Chinese officials, just after Beijing appeared to against Tehran over its uranium enrichment program.
China has veto power in the U.N. Security Council and ending its opposition would be key to passing a resolution against Iran, which is suspected of developing nuclear weapons. Tehran says its nuclear program is for peaceful power generation.
In February, China said Obama's meeting with the Dalai Lama "seriously" hurt bilateral relations. It summoned U.S. Ambassador Jon Huntsman to protest.
Other world leaders are expected to attend the nuclear summit, including British Prime Minister Gordon Brown, despite a likely election campaign in his country. Brown is widely expected to call general elections for May 6 - meaning the visit would take place as Brown's governing Labour Party and its rivals are launching their campaigns.
After Washington, Hu will travel to South America. His stop in Brazil will include a meeting with leaders of Brazil, Russia and India. The four major emerging economies are seeking a greater say in the world economy, including a greater role in global financial institutions.