Ahmadinejad will be attending Expo Shanghai 2010, but will also meet top Chinese officials to discuss Iran's nuclear program, the threat of sanctions and a fuel swap deal for a Tehran research reactor brokered by Brazil and Turkey last month, Iranian state television reported on Monday.
His visit to Security Council veto-wielding permanent member China takes on particular significance as a vote on a new sanctions package looms after the United States introduced a draft resolution last month.
China, which has emerged in recent years as Iran's main trading partner, continues to insist on diplomacy to resolve the standoff over Tehran's nuclear program but US officials say they have Beijing's support for the sanctions resolution.
Before heading to China, Ahmadinejad was due to hold a round of meetings in Istanbul where he was attending a regional security and confidence building conference on Monday.
He was expected to meet Prime Minister Vladimir Putin of Russia, another Security Council permanent member, media reports said.
He was also due to meet Turkish Prime Minister Recep Tayyip Erdogan to discuss the nuclear fuel swap deal.
On May 17, Turkey and Brazil brokered a deal with under which Iran agreed to ship 1,200 kilograms (2,640 pounds) of its low-enriched uranium (LEU) to Turkey in return for high-enriched uranium fuel for the Tehran reactor which would be supplied later by Russia and France.
The deal was cold-shouldered immediately by Washington which has ratcheted up diplomatic pressure for a fourth set of UN sanctions against Iran for continuing to enrich uranium in defiance of repeated Security Council ultimatums.
The US secretary of state said on Monday that world powers have the required number of votes to pass the sanctions resolution.
Clinton said she expected Iran would "pull some stunt in the next couple of days" to try to head it off.
"I don't think anybody should be surprised if they try to divert attention once again from the unity within the Security Council," the top US diplomat said.
'Standing in the face of enemies'
Senior US officials have said they are forging ahead with the resolution without Brazil and Turkey, two non-permanent council members who insist that fresh sanctions would be counter-productive after the nuclear fuel deal they brokered opened up the opportunity for further diplomacy.
Asked if she was worried about opposition to the sanctions resolution among non-permanent members, Clinton said: "We'll wait and see what happens, but we have the votes."
US officials say the resolution has the support of all five council permanent members – Britain, France, China, Russia and the United States.
For the resolution to pass, Washington will also need the votes of at least four of the 10 non-permanent members.
US officials have said they expect the resolution to be put to the vote later this month.
On Friday, Ahmadinejad said Iran will defend its rights even if new sanctions are imposed.
"We are standing in the face of enemies. To defend the rights of the nation, we will pull out any resolutions from the mouth" of the enemies, the hardliner said in a speech marking the 21st anniversary of the death of revolutionary leader Ayatollah Ruhollah Khomeini.
Iran is already under three sets of UN sanctions for enriching uranium at its nuclear facility in the central city of Natanz.
Western governments suspect Iran of seeking to develop a weapons capability under cover of its civilian nuclear program, an ambition Tehran strongly denies.