With the recent change of the US security policy on the one side and China’s rise as a global economic power on the other side, a lot of academic debate has focused on the power transition theory: seeing China as a rising power and the USA as the status quo power the question is how the global power dynamic between China and the USA will develop? This paper explores the ramifications for China of the US withdrawal from the 2015 Joint Comprehensive Plan of Action (JCPOA). From the Iranian side, the aim of the JCPOA was to have the Iranian economy integrated into the world economy, which would help Iran overcome an ever-increasing economic crisis and turn Iran into an attractive market as well as an important exporter of oil and gas. For USA and the international community, the overall aim was to avoid Iran being capable of developing nuclear weapons and avoid that the international crisis and conflict of the Iranian nuclear program would lead to an open war. Many states and companies also expressed a significant interest in the opening of the Iranian economy, giving them access to the market, to investments, and to the import of Iranian oil and gas. China has increasingly expanded its economy investments towards The Persian Gulf. China’s increasing economic interest in Iran was slowed down before the JCPOA because China did not want to challenge US security policy in The Persian Gulf. After the JCPOA, China again increased its activities with Iran. How will China react after USA in 2018 withdrew from JCPOA and resumed sanctions on Iran? Although unilateral sanctions, USA has made it clear that third parties who continue dealing with Iran will be punished, which has already led to a halt for activities for many European companies in Iran. Will China fill in the void? Will China challenge USA by increasing its trade with Iran? The public statements in China are ambiguous. Studying China’s economic policy in Iran after the renewed US sanctions can give us more clear indications of how the rivalry between China and USA will develop, making it possible to analyze the global power dynamics between the status quo and the rising power. The paper is based on research, public documents, and interviews during study trips to the Middle East and China.