In March 2021, Iran and China signed a 25-year cooperation agreement that will strengthen the relations between the two countries and include "political, strategic, and economic" components.

The Parthians and Sassanid empires (occupying much of present Iran and Central Asia) had various contacts with the Han, Tang, Song, Yuan, and Ming dynasties.

The Han dynasty diplomat and explorer Zhang Qian, who visited neighboring Bactria and Sogdiana in 126 BCE, made the first known Chinese report on Parthia.

Following Zhang Qian's embassy and report, the Han conquered Dayuan in the Han-Dayuan war and established the Protectorate of the Western Regions, thereby opening the Silk Road and clashing with Persia sphere of influence (as some satraps were part of the conflict).

They cooperated in guarding the trade routes through central Asia, and both built outposts in border areas to keep caravans safe from nomadic tribes and bandits.

In 751, the Abbasid Caliphate, which ruled Iran, was in dispute with the Tang dynasty of China over the control of the Syr Darya region during the Battle of Talas.

[7][8] In the 1220s, the Mongols sent Khitan and Han Chinese administrators to Bukhara and Samarqand to govern, and this was witnessed by Qiu Chuji on his way to meet Genghis Khan in Afghanistan.

[15] The Mongols sent new people to repopulate the Jaxartes river (lower Syr Darya) and the city of Yangikent (Iamkint or Sakint) after deporting and killing the natives.

[27] Han Chinese were sent to the Upper Yenisei valley as weavers, into Samarkand and Outer Mongolia as craftsmen, as noticed by Ch'ang-ch'un in 1221-22 when he travelled to Kabul from Beijing and they moved to Russia and Iran.

In his wake, he left many relics, including the Chinese-Persian-Tamil Galle Trilingual Inscription, praising the Buddha, Allah, and Vishnu, respectively, in the three languages.

[54] In fact, after the JCPOA was signed in July 2015, China and Iran agreed to expand trade relations to $600 billion in ten years from January 2016, on the occasion when Chinese leader Xi Jinping paid Hassan Rouhani a state visit.

In March 2004, Zhuhai Zhenrong Corporation, a Chinese state-run company, signed a 25-year contract to import 110 million metric tons of Liquefied Natural Gas (LNG) from Iran.

The deal, worth $100 billion, adds an extra 250 million tons of LNG to China's energy supply, to be extracted from Iran's Yadavaran field over a 25-year period.

China would need no prior permission from Iran's government to maintain and increase its military presence in the country, and would control the movement of Iranians in and out of these territories.

[58] Once profitable trade relations were established, the PRC invested in Tehran's subway systems, dams, fishery, and cement factories while Iran helped supply China with the highly desired minerals of coal, zinc, lead, and copper.

[58][61] Trade between the two states also included power generation, mining, and transportation equipment, along with arms and consumer goods such as electronics, auto parts, and toys.

With the foundation of the coordinated shipping line between China and Chabahar, cargoes are conveyed ten days prior, whereas fetched of stacking and emptying is decreased by 400 dollars per holder, the official clarified.

[58] Even Chinese state-run news agencies upheld the validity of the internationally controversial election[specify] and ultimately attributed any problems that day to terrorists and vandals.

From this scrutiny, it became known that China was using North Korea to traffic arms during the Iran-Iraq war to avoid antagonizing the West, but later cut out the middle man.

In 1971, Imperial Iran supported Red China's bid for a permanent seat in the United Nations General Assembly Resolution 2758 and it voted in favour to admit Beijing and replace Taipei.

[75] In the 1980s, the shared ideological themes of anti-imperialism and third world solidarity helped solidify the relationship, but they became allies as a way to counterbalance the Soviet Union and the United States during the Cold War.

[58] Since Iran no longer recognizes the ROC, now residing in Taiwan, its representation is held by the Taipei Economic and Cultural Representative Office in the Kingdom of Saudi Arabia in Riyadh.

While there is also a shared distrust of the United States' government and its interests, many young Chinese and Iranians at the same time admire certain aspects of American society and culture.

[61] Beijing has generally supported the Iran-backed government of Bashar al-Assad in Syria, joining Russia in vetoing several U.N. resolutions condemning Assad's actions in the Syrian civil war, and strongly opposing Western interference in the conflict, arguing that outside intervention would further worsen and complicate the situation.

[102] In July 2019, UN ambassadors from 50 countries, including Iran, have signed a joint letter to the UNHRC defending China's treatment of Uyghurs and other Muslim minorities in the Xinjiang region.

[103][104] In January 2020, China condemned the assassination of Qasem Soleimani, with the Chinese Foreign Minister Wang Yi alleging that the targeted killing of an Iranian general in Iraqi territory by the United States was in violation of international law.

[109] In late 2022, Iranian Foreign Minister Hossein Amir-Abdollahian was reacting to a joint statement issued by China and states of the Gulf Cooperation Council, which called for peaceful resolution of the islands dispute with the United Arab Emirates.

Although the two societies psychologically identify with one another because they both share the national pride and historical identity that comes along with being the descendants of two great empires and modern successor-states to ancient civilizations, there was limited interaction after the Chinese Communist Revolution in 1949.

At the same time, Persian women also intermarried with Chinese men: see Lin Nu, Liu Chang (Southern Han), Wang Zongyan (married Li Shunxian), and the Zhengde Emperor.

Oddly, these loanwords are typically themselves loans from a pre-Iranian substrate, e.g. Elamite or BMAC:[143][144][145] Huihuihua is a dialect of Chinese with more Persian and Arabic words.