The present article has been compiled with a historical-analytical method and with the aim of examining the relations of the Sassanid government with China in economic and political dimensions. With the fall of the Parthian dynasty and the repression of the Kushans by the Sassanids, Sogdian merchants replaced the Kushans in relations between Iran and China. The findings of this study indicate that factors such as the Sassanid Empire's rivalry with Eastern Rome over the monopoly of silk products, the choice of Sassanid silver coins in the exchange of goods with Rome, etc., the creation of ports on both sides of the Persian Gulf, immigrants And new cities in Central Asia, and the residence of the Sogdians in the cities of Luoyang and Chang-an, expanded economic-trade relations between Iran and China. from the time of Ghobad I to suppress Hayatleh, the era of Khosrow Anoshirvan to suppress the Turks, and then from the time of Yazdgerd III and his descendants to suppress the Arabs, Khaqan was asked for help from China, which, although unsuccessful, caused relations between the two countries Find political. After the death of Yazdgerd III, Khaqan recognized his son Pirooz as the "King of Iran" in a small area of ​​Seyhun, but the Arab invasion of Takharistan resulted in Piroozh's asylum in China and made him one of Khaqan's officers. The efforts of Narsi, the son of Pirooz and Bahram, the son of Yazdgerd, also failed in attacking the Arabs, and since the Sassanids were considered a danger to the Khaqan remained silent in the face of the third Yazdgerd descendants between the Arab and Eastern Turks.