The Asian giant and the Middle East’s foremost Shiite power aim to build economic ties worth up to $600 billion within the next 10 years, Rouhani announced.
The two leaders oversaw the signing of 17 agreements in areas including politics, the economy, security and cooperation on peaceful nuclear energy.
“With the Chinese president’s visit to Tehran and our agreements, a new chapter has begun in Tehran-Beijing relations,” Rouhani said in a televised speech, flanked by Xi.
It is the first visit to Iran by a Chinese president in 14 years, according to state news agency IRNA, and comes just days after sanctions against Tehran were lifted under a historic nuclear deal with world powers.
“Iran is China’s major partner in the Middle East and the two countries have chosen to boost bilateral relations,” IRNA quoted Xi as saying.
“China and Iran are two important developing countries that must continue regional and international cooperation,” Xi added.
Beijing has long taken a backseat to other diplomatic players in the Middle East but analysts say the region is crucial to Xi’s signature foreign policy initiative — known as “One Belt One Road” — touted as a revival of ancient Silk Road trade routes.
China, the world’s second-largest economy, also relies heavily on energy imports from the Middle East.
Beijing is Tehran’s top customer for oil exports, which in recent years were hit by US and EU sanctions over Tehran’s nuclear programme.
Trade between the two countries was worth $52 billion in 2014. They did not give details of their goal of developing relations worth $600 billion over the next decade.
According to Iranian media, more than a third of Iran’s foreign trade is carried out with China.